CHARGED FOR CONTRACT THAT ENDED IN 2010

I have a contract with Virgin Mobile in 2010. I paid it and still in that year I brought my phone in to be repaired at the Umhlanga Durban branch. I followed up and never got the phone back up until I moved from Durban. I have never received a statement from Virgin Mobile. This week I get a call from debt collectors DMC saying I have to pay Virgin Mobile for my contract from 2010. What the hell am I being handed over for????? When am I going to receive my phone back. I have contacted Virgin Mobile 3 times this week and no response, the last thing they asked me was for my ID number and they have not said a word since. They debt collectors are calling me every day. Please can SOMEONE at Virgin Mobile attend to this and sort it out.