MTN ,just never respond on all my complains

MTN want to take me to court for not paying for a cellphone on contract,which I bought in Nov 2013 and send back also in Nov 2013.<br> I wrote several letters of explanation,no reaction.<br> I wrote here on Hello peter the problem on 24 July 2014,only a letter follow,that they will look into it,but that's all.<br> I received now a call a month ago,that they want to sue me...What can I do,to get some service from them?<br> I don't have that cellphone.The number of the phone is ***.MTN can go look and see,that it has never been used!!<br> V van niekerk