Tell on online contract from hell

Nightmare Telkom contract account I took an online router with telkom last year March. I learnt that the router was not functional and then I returned it to them within 7 days as the contract states. I called to cancel the contract but a year later telkom is still debiting my account and blacklisted my name. I tried calling several times for assistance, I stay on the line for almost an hour waiting for assistance to only end up with false promises that it's been cleared. The worst is that I'm being told no telkom store will assist as I took the contract online. This is affecting my finances negatively I'm at the point where I cannot get any contract even a house loan I'm hoping hello Peter will be able to assist me