Shocking, MTN!

This is very unfortunate but they leave me no choice. I’ve logged 2 cases with MTN - querying why I got billed double the amount and been trying to cancel one of my contracts. The only way to cancel is to dial 135 & select option 3. I’ve done that 3 times and waited endlessly to no avail. Now they are still going to charge me cause it’s impossible to cancel a contract. This is not right and probably not legal!