Home Internet

I need to express my extreme frustration and disappointment with MTN South Africa. I opened a Home Internet contract with them last year. They advertise that you can cancel this contract anytime. I phoned customer care to downgrade this contact from a 20mps line to a 10mps. The lady was very polite and helpful but a few weeks later, after paying for the new router, I realised I had no confirmation of the cancelation. When phoning customer care again, they told me I can only cancel in store, and not over the phone. The very polite and helpful lady did not tell me this. I then emailed asking for the policy or contract that I signed where these terms were agreed to and I have had no reply. I have explained that my nearest MTN store is 100km from my town. I have mentioned that I am happy to pay for a courier to collect my old router. I have spent countless times on the phone trying to reach someone who can help me but they only send me from department to department until eventually the phone goes dead or someone makes me a promise that is never kept. I am now approaching the second month where MTN are going to debit order me for a contract that I no longer need and have tried to cancel many times. Their service has been appalling and I'm now quite exhausted. Hopefully someone who cares can see my post and help me with my situation. Thanks a lot MTN South Africa.