***** or just plain theft?

Deducting monies and delivery the modem when I registered for the service was prompt. They reacted slowly to collect the modem when I cancelled the service, but it was done. However I have trying to stop the payment for 5 months - since May 2022. Rain service center assures me all is done, a refund will be done, yet another payment appeared on my bank statement in October 2022. If payments can be started so quickly, why can it not be stopped with immediate effect. This was supposed to be a month- month service.