I don't think GMs give back stolen guild names. But if you can prove that guild name was sold for coins, you can try to make a support ticket in game since such trades with coins are not allowed. If that doesn't work, you will have to make a new guild with different name.
Thanks for the reply, working on it with GMs, but they want screenshots for proof, but I'm like, how am I supposed to have screenshots of him receiving coins? lol
This really sucks cause I went on hiatus cause I'm having a baby soon and also studying for my A+ cert. Such a bummer how someone you "trust" takes advantage of you like this.