Well, with some being only donates, a guild could invest a ton of bucks to get a ton of them. With this in mind, if the items or the currency used for that can be traded/sold/etc, it's just a small step to have the basic items needed in some quick days.
BG gear can be done fast if the server have it most of the time on. Dunno how active it's there but some guilds share accounts around their core members since they're playing together for ages and when someone is done with BG gears at his/her char, they just change to friend's char and keep doing it. If they never set a foot there, then that's another story and is fishy.
Also, the server doesn't have a Guild Pack, right? Some server have some that make a guild be like insta ready for action with some quick minutes of farm a couple of days.
And I would believe at you based on his past as many others would do too but nothing is 100% sure without evidence since anyone can use his past to spread bad things about him.
The best I can advice is to see if someone got any proof and ask to send you to post here or tell them to post it here but remember, Cookie/Cawliflower is already at the Hall of Shame so this won't change that much the current situation since it seems that people keep joining the server after reading everything here and there. If they still join the server then nothing is going to stop them from playing there except if the server dies.
The max to do in here, if you want, is adding a quick list with guild/players that have made that[if it's true ofc] so other players can see what they're facing and if they still want to play with them knowing that or want to still being there facing them for the challenge provided.
If no evidence is provided then it's up to people believe on whatever they want. Your story, others story or get into the server and see for their own eyes and make their own judges.