incorrectly billed for R5224

I took a contract with Telkom mobile. I ported my number from Mtn.I experienced poor reception and it stated emergency calls only. I then went on to cancel the contract within 7 days. The Telkom mobile store in Benoni did not know procedure. He refuse to give me my sim. He said that I will not be able to make calls until my number is converted to prepaid. I had no phone and no number. When I tried to port the number back to mtn,they said that I have to wait 3 months. I called the call centre only to find out that I have a bill of R5224 for penalty costs. They did not cancel my contract before 7 days . I kept on calling the call centre they said they logged a case. My account was then debited with that amount. The call centre agents admit its a mistake but cannot tell me when the problem will be solved. I spoke to a call centre team leader Sydney, he keeps on avoiding my call and promises to call back. I don't know who else to speak to because his manager always seems to be busy.. No one Knows what's going on..I need help. They do not have proper systems in place. It was a simple cancellation of contract. i still cannot use the prepaid number due to reception. Help!!!!!!