I am in the same position as you but for £18. I have written to them (again). Still waiting for a response. You can have a 'dispute statement' added to your credit file (contact credit reference agency) Send a Subject Access Request to Lowell. Be patient as they have 40 days to reply. You will then see (if they respond) what the debt is. You will then be able to dispute it if it is wrong. you are quite right that paying it off is not the solution unless you can get Lowell to agree to remove the entry - which they do not do! I fully intend to pursue Lowell through the courts if necessary. Will update!