dissatisfaction of service delivery

I am unhappy with the services I got from the Adt Security Company, I signed a contract around August 2020 which was the continuation of the first contract I signed on October 2018. the premium for the first contract was R556, then later reduced to R380 and later when I went through my bank statement I realized that the amount has not been changed. when I wanted clarity I was told that it was not captured and I wont be reimbursed. Can you please assist!.