Matam2k. If all they have the details of your Debit Card, then cancelling or 'losing' your old one and getting a new one will stop any post dated Debit Card payments they may have going through.
I do on occasion use Payday lenders, luckily never to have had problems repaying. So once your debit card has been stopped the balls in your court. I'd recommend calling the companies up and making them an offer of repayment. i.e. £20-£50 p/m per lender? Tell them you are in financial difficulties due to over committment and see if there's a possibility of a suspension of interest and charges. The rationale behind that being that they would rather re-coup some of their inital capital then loose it all (damage limitation)
Don't what ever you do keep rolling over, its money down the drain!