non ending calls and messages to sign up for a package

I cancelled my DSTV account almost a year ago. Each week I receive multiple calls to reconnect the account and I have on so many calls politely explained why I cant reconnect my service. If its not the calls it’s the messages I receive almost daily. I have requested many times to be removed from the list of leads but my request seems to just fall on deaf ears. If a person says on a Monday that they are not in a position to reinstate the account and you contact them again a few hours and few days later and they continue to give the same response when do you as a company accept that this person does not want your service and stop forcing it on them?