A very unpleasant situation, which is another reminder that you should always read the user agreement before using any gambling site.
In my opinion, the gambling site should have programmatically made it impossible to bet from the bonus account on the listed games and introduced the necessary limits. Otherwise it all looks very much like a not entirely honest business, with its creators covering their actions with a user agreement.
We should also understand that these gambling platforms are out for profits and nothing will give out profit "if" there are no traps set for those who can't read platforms TOS. Something like this happened to me some years back with some online courier company, after placing my orders with the best deal, i forget to read about their agreement and when the time of delivering came they sent me some messages that my country wasn't among the country for such deals, then, return my funds and my account was suspended till-date.
I think that is not a trap because it is written on their TOS so when new people want to register on their site, they need to read TOS and understand the rule from the site. That will help the gamblers break the rule and safely play gambling on that casino. The recommended casino will not try to trap their members because that will relate to their reputations and if their members have a problem, they will help solve it.