Bad service and ******** people forcing them to continue paying their contract.

My name is potsiso Letsie ***). I took a contact Sim which goes with a phone on mtn in 2019 the beginning of the year and now I have been calling mtn to cancel contact which has expired for almost 2 months, the bad thing is that when I call their customer service they take my details then they transfer me cancellation department from there onwards no one will answer my phone it will keep on ringing without be answered because they know that my contract has ended.