MTN harrassing with phone calls

People are constantly calling me frim MTN. First they insisted to speak to my husband, and when I asked who is calling, as no introductiin had been made, the inform me that it is none of my business who is calling, and hang up. I have true caller app in my phone, so when I told them I know they are from MTN they got very rude and insulting. They sometimes call me 4x a day, and when I answer they hang up. Sometimes they speak, calling me by a name that is not mine, and when I correct them, they laugh and hang uo. Sometimes they aske me how I am doing, and when I say finr, they laugh and hang up. I have blicked their numbers, so now they are calling my moms phone, which is also on contract on my name. I can't believe that MTN can allow their employees to harrass their customers in this manner.