I took a contract on...

I took a contract online through Mondoo and I was only told after it was delivered thats its home data I told MTN and moondo I need the contract cancelled Asap that was in June 2021 till today the line is active and I’m told I owe them about R600 I got an email from monndo saying the cancellation was done but MTN says it’s active I’ve been on hold for 45 minutes and the call center agents are so rude