SNEAKY DEBIT ORDERSS

I have always been a very happy and loyal wonga customer until like many others I lost my job and was unable to pay my agreed repayment amounts and was handed over - this is fine and expected. HOWEVER no one gets back to you the collection agent called twice and never again - I called wonga so many times and no one can help me - cause now.,,, i wanted to pay. Anyway I manage to get hold of the collection agent but wonga is still sending through instructions to debit my account? HOW??? This is not acceptable - double payment? my account is being negatively influenced every month because there are no funds for this now unauthorized debit order- this debit order request needs to be cancelled IMMEDIATELY