RSAWeb - pathetic customer service

I have requested RSAWeb to cancel my internet service on 10th October. With a month notice, the service should get terminated on 10th Nov 2021. Now their customer service department is debating with me and forcing me to keep the connection till 30th Nov 2021. I have failed to make them understand that 10th Oct to 10th Nov is a month. Very upset with their response. Very bad service.