You should explain your financial situation in detail, and that you are unemployed. Explain that this is the first time they’ve asked about your income, and you have not mislead them or misrepresented yourself.
Suggest that if they no longer wish to take your business, they should allow you to withdraw your balance and close your account.
They aren’t going to withhold your money. They probably just won’t allow you to play in the future. If they suggest any significant delay, say that you’ll take it straight to dispute resolution. I’m sure this will be resolved amicably. Never had any problems with them.