You're definitely not the first nor the last one to have this issue. Actually, the current discussion on our thread is about unfair T&C as years of experience in the industry have shown that operators will do anything to void winnings won by bonus funds. It is what it is, though and it's a lesson learned. Everyone should always read the T&C and even maybe double-check with customer care before claiming and using a bonus to protect their winnings if they get a lucky streak.
It is a lesson to all of us not to avoid the T&C even in the reputable gambling site or offline casino because we need to know their rule and prevent not breaking their rule. The reputable casino, whether offline or online, will not try to cheat their members because that will be related to their reputations. And if their members have a problem, they will try to help and solve it because that is the important for them to make their members satisfy. But yes, we need to make sure that we know the rule and read all of the T&C on that site.I absolutely agree. Honest casinos that want to build a name for themselves won't do any tricks. But players also have the responsibility to read the rules and protect themselves. The OP admitted his guilt in this situation and hopefully learned a lesson.
But I also think that there should be possibly some tools or features that will alert players in such situations. Like, when you play with bonus funds and want to place a bet over $10 (if $10 is the max bet) to notify you that you will lose the bonus and the winnings. In my opinion, there should be some mechanism to inform users when they want to make something against the bonus rules. This should be a fair approach toward everyone involved. I think that casinos often take advantage of players being too careless and not reading rules and then they have the perfect excuse to do such tricks.
In the case mentioned on this thread it didn't have a bad end, because the deposit made by OP was re-credited, so he could try again from zero, but I have seen cases where the payment was just denied, including the initial deposit.