Telkom bad service

Hello Peter telkom is taking me for a ride, someone called me from telkom offering me a an upgrade through the phone. After a day I received a new phone and I didn't like it so I called them to cancel the deal and they didn't want me to cancel it, they keep on cutting my calls and claiming that their line was bad. Eventually I called other number and they canceled my deal with my contract sim blocked. So I wanted my sim card to be unblocked, they told me to wait for 21 days and now it's been more than 21 days still my sim card is blocked and they have sent me a invoice for the month and I have to pay for the services I am not using