You can make a complaint to the banking ombudsman if they are a bank, if they are a company you can also make a complaint to the FSA (financial services assoc.) they will be registered and will have displayed details on correspondence BUT, and this is the thing, I agree with 'Factor30', sort the debt out first and THEN make your complaints, if this goes to court, your alleged breach of the DPA will not hold any water as a defence for not paying. you can do both in tandem but you MUST sort out the debt. hope this helps.