Assuming the person was discharged from bankruptcy, & is not still subject to any bankruptcy restrictions, then they are is just the same position as anyone else.
A money recovery firm could only take money from their bank account under a Court order, which would only be made after a County Court Judgement had been obtained for a debt, & they had failed to abide by the terms of the order. The debt would have to be one incurred after the discharge from bankruptcy, as all debts incurred before the bankruptcy (with some very limited exceptions like fines) would have been wiped out by it.