The QR code is just a short cut link to their bank account. You can just ask for the account number and then transfer using wise or one of those companies with your home country account
I don't know any agencies but if you want to do it yourself and save a lot of money it's not hard to do. I paid for a 6 month training package with Phuket King for 15,000 baht and then applied. They have all the correct documents.
for once I will agree with you. 27k is a fair price and that gym Fitness Hero in Patong he got the price from is actually a really nice gym. Very clean and modern with good equipment, I have trained there before.