Worst client serive - Telkom SA

The client service from Telkom has been nothing but a nightmare for me. I ordered a laptop over the phone and the following day, they delivered an incorrect device to me. When I informed them, they had the incorrect device collected and delivered the correct laptop. BUT they never cancelled the contract for the incorrect laptop and they have been charging me for 2 contracts even though it was collected. This matter has been dragging for a year now and I have lost count of the number of calls I've made to them trying to get this matter resolved. Every time I call, I am told that they will log a request and no one bothers to get back to me.