Completely out of order sending me a letter inferr...

Completely out of order sending me a letter inferring that I have an outstanding debt. I am not sure what there angle is or the reason for the letter, as to my knowledge I have no unpaid debts and a credit rating of 990 out of 999. I would like to know who the large number of organisations that they claim to provide a professional service to are as far from being professional they are under hand and bordering on scammers.