Cell C *********** Staff

Having to repeatedly tell some one you are not interest in upgrading your contract. I have received about 15 calls from Cell C call centre offering me an upgrade and every time I inform that I am leaving the country and I don't want to upgrade my contract. Sometimes i get multiple calls on 1 day.I have asked multiple consultants to please put a note that informs them of the reason and yet ever 2-3 days i get a call from cell C. When i ask if a note has been added on the system I get told no and I am getting fed up repeating myself. So the next call i get from Cell C would be to cancel my contract. Because apparently the staff working at Cell C is ***********. How difficult is it to put a note on the system?