What else must I do to have my contract cancellef

I have been trying to cancel my telkom contract for the past 3 weeks without success. I went to their branch in Alberton and was told they can't help me I must do it online. It took me 5 days to eventually register because their OTP expired in 3 minutes and received their emails late. I sent an email last Friday requesting that they cancel my contract, still no response. WHAT ELSE MUST I DO TO CANCEL MY CONTRACT????