MTN insurance complain

I have a contract with MTN linked with two numbers one data sim and the other personal number which i pay around R 2500 with insurance and unlimited calls.. I was billed wrongfully for the past 12 months on my data sim for 40gig day and 40 night in which no before i cancel the contract i charged for 20gig day and 20 night in which its cost 600 and something. Then I sent my personal phone for repairs and payed all the access fees its been 2 months now since my phone is not properly fixed. Been calling the insurance people and requesting them to come re-collect the phone for a week since they say they coming and its been five days now waiting. Cause they know they need to buy time for my insurance contact (12 months) to finish. I cant cancelled both my contract up till my phone gets fixed and i will continue paying an unnecessary R2500 just so they can help fix my complains. Im still going to struggle cancelling my contracts