Bridge of contract

I signed a contract with DSTV for a price lock(R727) this was March 2020 and it is suppose to be for 24 months. March 2021 I got debited a different amount. I have been calling the call centre with no joy all of them promising to get the price lock team to call me back and that never happens. I spoke to Anelisa - ***#i205, Sagree - ***#2047 then Vuyokazi that decided to drop the call on me. I still didn't get any help.

Can someone just answer simple questions Why did DSTV bridge the contract? Why am I paying more than I am suppose too - even the R727 is incorrect as per your call centre agents (when they are trying to sound helpful)?