Reid was the first rider to leave New Zealand's endurance team for the World Games, followed by Jenny Champion, who withdrew last week.
"I still have that passion for the sport but I feel really let down by ESNZ, and how they've handled things. A groom issue like this should have been fixed in five minutes," she said.
"The bottom line is, we're paying for this [all riders must fundraise for their trip], why aren't we getting our grooms? The stupid thing is I haven't got a real reason why Pip can't go, surely 'unenthusiastic' and 'writing a poor CV' are not real reasons."
The first Reid knew that Mutch was not selected was when Mutch phoned her "quite upset" after receiving a letter from selector and Chef d'Equipe Madonna Harris stating that she had not made the team.
Reid was then told about a week later by a selector that Mutch "wasn't fit enough", despite there being no published fitness criteria, or a fitness test, for grooms, that she was aware of.
"Then I was told she wasn't a man, and she (the selector) said they were looking for more men to balance the team. I asked 'why did you kick John Stevenson off then?'
"I was getting angrier and angrier because they could not give me a good reason as to why Pip wasn't on the team," Reid said.
Then, at a meeting with ESNZ Friday week ago, Reid said selector and chef d'equipe Madonna Harris told her the official reason that Mutch did not make the team was that she was "unenthusiastic and wrote a poor CV".
Reid is struggling to understand Mutch being described as "unenthusiastic", given the amount of fundraising for the trip that she had undertaken before going to Scotland for a family holiday. Mutch, who owns Reid's mount Makahiwi Achilles, had already raised nearly $9000. "She was so excited to see her horse go," Reid said.
Makahiwi Achilles - known as Chilli at home - is the reigning national and North Island 160km champion, and earlier in his career Mutch competed him herself and rode him to a title win.
"She knows all his funny little quirks, and he's got them. I first rode Chilli four years ago, and Pip groomed for me then. That first year we came fourth at the nationals. So she's no stranger to the horse, and she's definitely no stranger to the sport. She's been doing it for over 20 years," Reid said.
Chilli is 15, the same age as Jenny Champion's mare, Freckles. "They're both older horses, more mature, and they certainly know what their job is," Reid said.
Reid said she was approached by Endurance New Zealand officials after both the National and North Island Championships to consider going to the World Games. "During talks at the Nationals I was led to believe that I would have my No 1. groom, Pip, without any problems. I was not made aware at any stage that there would be any problem with my grooms until they made the announcement in early July," Reid said.
Reid had applied for her daughter, Sian, to be her second groom, but was told that she would instead be her primary groom. "She was my second choice groom because Pip knows the horse better than anybody," she said.
She was told at the meeting in July with ESNZ that her second groom would be Braden Cameron.
"Braden's been in the sport for three years maybe, and he's a nice guy and I have no problems with him, but he doesn't know my horse or me at all," she said.
She withdrew on the 13th and this was accepted on July 16. "And that was after trying for over a week to sort it out with the selectors," Reid said. "But after (selector) Pauline King told me there was probably no chance it would be sorted, I sent in my resignation."
"Chilli does have a few issues, and if you do something wrong, it could have put us out of the ride. He has issues with rugs going on and off - if you do it wrong he's likely to try to take off, and he could get hurt quite easily if you're not aware. It's just little things like that. You don't need to be worrying about things like that in the middle of a big competition. I just wanted to get over there, with the team I have around me, and really give it everything. And he is a great horse. I thought he had a really good show to do very, very well," she said today.
"I'm devastated. For the first two weeks I was really upset, but this is now five weeks old and I'm still trying to fight my way out of the fundraising, and apologising to people. I feel I've let a lot of people down. The community around here had gathered around me really strongly," she said.
Reid said all the riders on the squad have to fully fund their own trip, to the tune of $35,000 for return flights alone for each horse. "The only condition that Chilli went, was that he came home again," she said, "so we were trying to raise the $35,000 to do that. I believe the price has just gone up in the past 24 hours by another $12,000 as the horses are now going to the US via Asia, rather than direct from Auckland to Los Angeles."
The $35,000 didn't include any feed or stabling, which Reid estimated would have added another $10,000 to the cost of the trip.
"Before this all stopped about five weeks ago, we had fundraised just under $13,000, and I had a couple of big events planned this month. We were well on the way with fund raising," she said.
"It's been gutting, I've had so many sleepless nights, and have been trying to explain to the local people why I'm not going. Most have been really supportive, and have said I can't go unless I'm confident that I have everything around me that I need."
The funds raised which did not go to the endurance team would now go into a local fund for a representative sports person from the area.
Reid will campaign Chilli again this season, and is aiming to get to the North Island and the National championships again, as well as the Tom Quilty ride in Australia next year.
But other major wins would likely not make up for losing the chance to go to the World Equestrian Games.
"It's a big disappointment. Representing their country is something everyone dreams of.
"I won't say I would never put my hand up for it again, but I would be surprised if I did, after all this."
Warrick Allan, High Performance Operations Manager for ESNZ, said today that early in the season expressions of interest to be a groom for the 2010 WEG Team were called for, and riders were asked to nominate their preferred number one groom, "as this allowed the selectors time over the season the to watch those put forward in action".
He said that more grooms registered than there were positions available for, so on June 13 all applicants were asked to submit a CV before the final appointments were named.
A further statement from Equestrian Sports New Zealand is expected later today.