Paying for a tablet that has been in for repairs

I bought a tablet on contract from Fonechice in July 2014 however it broke in September and I sent it back to Fonechoice for repairs. I am not happy that I have never received a call from fonechoice regarding the phone I am the one who calls and 7months down the line I still don't have the tablet back so I also stopped paying for it in January because I cannot keep paying for what I don't have. I still haven't got any feedback from them instead they are now harassing me for payment and I will not pay until I have the tablet back.