Poor service

I took a service plan with innovation group, they said my contract is 24 months and now I am told I have to pay for 30 months and now they are taking long to answer their calls and they hang up. we use money to call. Can someone give me a call. They did not even pay full amount for my service I had to pay extra yet I pay them monthly. I need a settlement letter and my contract sent to me. I was speaking to Lindiwe on the phone when I ask for the details of settlement and she said I will have to call them yet I am online with her.