They are bastards! I had similar problem with Vodafone! Finished my contract...notified them 2 months in advance that I won't be re-newing contract...paid my last bill (it even went out as "last payment" on my bank statement)...few months later I had letter asking for another £90!!! Which I ignored...few letters later and them threatening with debt collectors - I just paid it within 2 weeks they gave me. Then few months later went to take a loan out (had one before, no problem) and bank refused it... Contacted credit history company, got detailed report- and mark was put on by Vodafone for not missing some monthly payments... I had DD set up, and payments were always on time which can be proved by bank statements...so credit history company contacted Vodafone on my behalf to see if they can cancel "black mark" due to their error...but they said "all information they provided is currect".... Was so annoyed, it's unreal!!