Monthly airtime

I have a contract with MTN and normally my cutoff date is the 13th of each month. On the 15th I checked my balance I had about R197 something and I made a call which lasted about a minute, but when I checked my balance on the 16 I had nothing only voice bundle onnet, I called customer service and spoke to the guy called Luyanda who promised to take the matter up with the superior and come back to me on Saturday, I am so ****ed because all I get from MTN is phone calls reminding me that I'm only left with 2 month before my contract elapsed, if surely they cared about me more than my money they could have sorted this mess, maybe a big fat maybe I could have considered to renew but if this is the service they offer and offered as this was not the first incident then I'm gonna have a veeeerrry long two months