biggycash

I deposited 50€ some days ago and recieved the 100% deposit bonus if I wager it 40x. I managed to hit a big win and after the 40x wagering I had 920€ so I decided to cash it out. The next morning I recieve a mail that they have made a "mistake" and that the bonus was only eligible for trustly deposits and consequently they cancelled the withdrawal and kept every penny except the 50 I deposited. The bonus didnt say anything about a trustly promotion and why would they even give me the option to recieve the bonus if I used the "incorrect" deposit method?