cancellation

I cancelled contracts on the 24th of February 2023. Received an email with a reference nr on 2nd of March 2023 that contracts is being cancelled. I still get billed every month for it. When you phone they say it is still in the process of cancellation. On their website it states up to 20 working days for an cancellation. It is now working day 58 and still not been cancelled. And you must just pay otherwise they handover your account although you have proof that the delay is on their side