MTN call centre harassment!

for the last 6 months my husband and I receive about 5 calls a day from MTN. they are trying to sell us a contract and the more we say no they more they call. it is harassment!!! we have both asked them to remove us from the calling list, to stop calling us, they are so damn rude - now they just miss call! it is harassment on another level! i am not interested! MTN stop ****ing calling!