Given run arounds by MTN when it's time to cancel my contract

I have been trying to give notice to cancel contract(router) which is expiring end February 2026. Been to different MTN stores and told I should call 135. Seeing I couldn't get the right option, I decided to call again at a branch, MTN The Glen in Jhb South on Friday 23 January 2026. The guy who attended me told me to do the cancelation telephonically as they don't do it at a branch. I explained that I've tried calling several times but could not get the right option. I asked him to also try to call on my behalf. Boom, same thing happened. He then decided to take me to his computer so that he can send an email. He told me I will need to pay R586. I don't know what was that for as I wasn't buying anything. Again, he said I should come back on the 1st February 2026 to give notice. Can someone assist me, I need to cancel my contract. Who should I talk to now?