Telkom took the unused phone back and billed me R15000

I took out a phone contract but realised my mistake 1. Husband getting retrenched and 2. The phone cannot support my apps and gadgets (this after the Rep said it would). So within 5 days I took the phone back and canceled this contract. So I have no phone and no contract. Now 1 month later I get billed R15000. I have nothing to show for the R15000 and it was canceled within the cooling off period.