Harrassment via so-called attorneys!

I am being harrassed by these 'attorneys' (can they really call themselves that???)! They say I owe MTN money for a number I don't even know. They are unable to send me the MTN statement which I have asked for countless times! Eventually I paid the measly sum to get them off my back. They continue with the rude calls and sending messages, even to my husbands phone now. Is it possible to open a case of harrassment against them?I will investigate further. Unfortunately one can't speak to MTN unless one has a number otherwise I would have this sorted out that way. Having looked through some of the complaints here concerning them, I'd say we have a case!