Billed for dsl which I didn't order.

Activated my line in a rented house, after a month I get my invoice which is now 2 months worth, which is fine, however I note that I am being charged for dsl. I did not order it (I have been using a different ISP), I phone and keep being directed. Eventually I get told that I need to downgrade my account by emailing to cancellations. I do this and get told they will respond in 21 days, its been 2 months. I have now gotten my 3rd invoice and still I am being charged for dsl. On the edge of contacting the ombudsman and creating a massive stir as this goes well against the CPA on both ******* charging and not returning/canceling/downgrading my service after 21 days of notification.