How to get out of my t mobile contract?

I recently bought a iPhone 5 from apple and bought it handset only, however after I bought it I realised that the company my network was with did not have nano sims yet so to see if my iPhone was working I decided to change network to t mobile and got a nano sim with them I did not set up a direct debit or anything… Jus had the sim from them based on a 12 month contract for £10 a month however I didn't really like there network service so after a month was up, my old network company had nano sims and I went back with them. However I didn't pay t mobile for the month as I didn't want to remain with and went back. I also thought that if I don't pay they will cut my line off which was ok. However I now received a letter saying because I didn't pay my line will be discontinued and my details will be passed on to debt collection agency and credit reference agencies which may affect my ability to obtain a mortgage in the future etc I just wanted to know what is the best way to put a end to this contract shall I phone t mobile and say I want to cancel but then they will probably charge me a cancelation fee etc… What's the best way to get rid off this…

Write to them pretending to be your next of kin, informing them that the customer has gone missing.

T mobile is a window phone with exprence keep learning

Whatever you owe them i suggest you pay because believe me if you don't you will never get credit for anything in the future.

Say you're not happy with the phone or deal and tell them I want to cancel

Say your out of commitment and end the contract