Problem caused by your funds being low: Checking or savings account

I have a debit checking account with Moneylion. They supplied a " virtual card '' that I do not use, and they allowed a fraudulent $99.00 charge, when there was only $13.00 in the account. Their own documentation states they don't allow overdrafting. So even though this $99.00 charge was fraudulent. at the very least, this transaction should have been Declined. They refuse to reverse the charge, they refuse to provide evidence why, and make it next to impossible to appeal.