Deceased's contract cannot be closed

I cannot get MTN to cancel one contract for the life of me. My husband passed away, I then sent all the document's to their legal dept. they required 4 times after they keep asking for it over and over! They drop the line when I eventually get through to them and query what more needs to be done. I am 73 years old and stood in a queue for 2 hours at MTN Richards Bay to close that one contract of which I was then informed the contract is now closed, yet I get another statement to pay for that particular contract and when I called them they also informed me it was not closed! What more do I need to do MTN? Perhaps someone on here can tell me what more to do as I'm dumbstruck. They are quick to sell you a product but never help with a problem and love to drop their lines!