Stinking service

I took out a contract in 2009 through a call center and I was informed that i can cancel the contract provided I pay for the handset which was a Samsung E250 which, I paid R1851 in 2010 u to today this is still reflecting as a debt. This is so poor that after 5 years they still cant reconcile their accounts. My life has been affected negatively by this ******* and I have a problem with this. I called in a few times to sort this out at head office and i spoke to a lady who dropped the phone in my ear .The stuff attitude is stinking and they keep on talking other clients rudely . I am tired of this and if i don't get a call from someone to resolve this i am coming there with a gun to make my sense of my case