Spam Sales calls

This is getting ridiculous CellC The number i have is not a CellC number but in fact a Vodacom one yet you still try and sell me contracts. I calls 5 to 6 times a day and now I have had enough. I have told each and every person that calls that I am not interested. I have also asked for my number to be removed from the calling list but I still receive calls daily. ***9