Cancellation not going through

I cancelled my mom's cover due to financial constraints, I was requested to write a letter which we did. To my suprise they continuing to debit my mom's account for the cancelled cover even after serving the 30day cancellation notice. This is messing my mom's credit and we cant leave money in her account with the fear it will be debited by Medshield.

I am tired of soeaking to people with no solution and minth end comes still same issue. The company has proven to have terrible customer service thus far.