Instant deposits are long time gone because majority are really requiring at least 1 confirmation in the network before the deposit would reflect out into your balance
and with regards with double spending issue then this is the main reason on why they do changed up routes or set up to be like this.
Or the reason could be different, so we can speculate on things until the actual response arrives from the security team why the account was put on hold. This double-spending issues also can be a reason for that but it's less likely to be in particular.
Most likely it's double spending on why they locked the account.
But yeah, hard to speculate until the security said what actually did happen.
Just recently my friend's account on other bookies got locked because of this but it got resolved by talking to their security team as they tell him on what to do.
I hope wecanbothwin will update us the status of his case.
Sure, waiting for the update and cause of the case why the account was locked.