possible phishing problems.

Hi there.

I need some advice for a problem that never seems to go away. Today, I received a letter which I thought was addresed to me. The previous owner of my house has name which is very similer to mine and I opend the letter thinking it was for me.
Yet again I got a letter from a so called debt collection agency acting for a company called Granada asking for money. This is not the first time I have received these letters and I have forgoton how many times I have called these companies telling them the gentleman concearned no longer lives here and to please stop contacting this address. For about six months, everything is fine, then all of a sudden I start getting letters again, from another company.
Can anyone help, as I am getting so sick and tired with this situation. I tried to find out who Granada are but due to the data protection act, these debt agencies refuse to tell me.
any help would be great.
Yours in frustration.

many thanks for the reply.

I have gone through all the motions, I sent back loads of previous letters, with not known at this address on them, unfortunatly they still kept coming. The previous owners of my address seem to have had some money worries and the DCA's still kept sending letters to my address thinking these people were still here. In the end, more in desperation, I contacted these DCA's and informed them politly that the people they were after no longer lived here. Unfortunatly six months later, new letters, from new DCA's, started appearing through my letterbox asking for payments for the same debts. I have phoned these DCA's and told them the same thing.
I feel I am in some sort of repeating cycle and am desperate to put an end to this whole sorry mess. Can the Financial Ombudsman service help, as i fell this is bodering on harrasement.