MTN must pay back my money

My name is Mokhele Motjope n contact number is ***…I app**** for iPhone 11 MTN contract phone through mondo and I was told that my package is 487 including insurance it will be 600.when my phone came same day it came with two SIM cards and i immediately called MTN n mine to ask about the sim cards and I was told that is an extra added package for data and asked them to cancel it.I was told that since I called with 10 days to cancel for the second SIM card the cancellation will be free,however for the month of July I got billed 879 if not mistaken and I called them again and I was assured that it’s only pro rata and activation fee and my instalment for the month of August will not include any cost besides the phone and insurance. Sharp month end of August to my surprise I paid 1103,called n didn’t get help till I went to MTN yesterday n again there at midlands mall I did not get help but was given a reference and number to call mondo,I did today and mondo told me that I must contact MTN they are the one who will assist,but even this far I still can’t get help and am paying for something am not using and that it was cancelled.here are the reference I was give both from MTN n mondo

MTN ref *** Mondo sr#***,

Number cancelled in question is ***,,,when you call them they will transfer u from one consultant to another.no one will tell you that let me help you with your problem but everyone will listen to you and say let me transfer you to the right department.yhooooooo I had it with MTN and I want refund for money money.they misled me and worse part am baying for something am not even using.long cancelled on July at the beginning

Regards Mokhele Motjope/***