Unfair Billing and unprofessional service

I opened a month to month contract on the 08November 2023 and I paid R150 immediately, Contract was R150 per month on a month to month basis . 30November R243 was debited from my account,01January 2024 R168 was debited,30January 2024 R168 was debited 01February 2024 R178 was debited and now got a message R178 will be debited. I send numerous emails asking for assistance as to why am I billed R178 instead of R150 which we agreed on with no success. May I please be explained to this time what is supposed to be my monthly debit amount please .