threats of summons being issued

Mbd attorneys bought over my absa credit card and account debt. They have sms'd me with threats of issuing summons to me even though I pay as per my agreement every month and havent skipped one payment. They are trying to blacken my name and credit scoring worse than what it already is. 3 years ago I was medically boarded for mental reasons and I am unable to work. I pay what I can afford as a non working mother of 2 children. Why do they do this and stress me out mentally and emotionally?