Endless advertising after REPEATED please to stop

I have made ENDLESS calls to the Cell C call centers, asking to be taken off of any and all advertising sms's, calls, etc..<br> First, I was told that it cannot be done and that I have to 'opt out' each and every time Cell C advertises something new via sms...<br> I was then told that I had been taken off of all advertising lists.<br> I have talked to agents, supervisors, managers, and its the same rhymes every time.. \You need to opt out each time".. Once I make it clear to them that Cell C refusing to stop contacting me with these adverts leaves me feeling herrassed"