I Regret choosing MTN as my network provider

I returned a phone at mtn store on the 26 May 2021 giving it time to go back to their warehouse since i ordered it online.I informed the online store on the 3rd June and was told the cancellation will take 14 days.On the 12 july 2021 i am still being billed for it, they keep on disconnecting my other lines which i am paying for, because of the phone they have.Despite calls emails tweets nothing has been done.If i had the money i would cancel my other 2 contracts and find myself another network because MTN is useless