WRONG BILLING ON MY ***

I was on the Black Friday price lock special for R750 since December 2018 and have been debited the R750 every month until November when i was billed the normal subscriptions due to my price lock contract expiring on the 6th of December 2019. On the 3rd of December 2019 i took out the new price lock special of R799, which means i have to be in credit because I was billed the normal subscription until the 20th of December and the new price lock kicked in on the 3rd of December. I got a shock on the 20th of December when i was debited with an amount of R1059.33. I have been calling DSTV ever since from the 20th of December and given reference number after reference number but no one is getting back to me to have this billing issue resolved. I spoke to Samuel on 20/12/2019 and given ref no ***, on 22/12/2019 I spoke to Tsepo and given reference number ***2-I212 and on 30/12/2019 i spoke to Mathapelo and given ref no ***2-I213 and she also advised that her manager/supervisor Edwin will phone me back later in the day before 7 but i'm still waiting on his call. My customer account with DSTV is ***2. URGENTLY assist to resolve this issue