Frustrated and Angry

I made an online upgrade in September 2019 but cancelled the next day, I've never received the phone but i'm contract has been updated. The contract current contract expired 16/12/2019, my bill must now go down from R299 to R99. January and February they billed me R299 and when complained several times they said its sorted out but that is not true. I even received an sms that my bill has been adjusted to R99 on the 20/02/2020 but come month end they billed me R299. They are busy taking me for a ride and a fool!!!