Mtn
BIS 50%

I activated my bis on the 2nd of march 2013 and today 21.3.2013 i recieve a sms from mtn reading " your.'ve used 50% of your MTN blackberry fair use allowance. To upgrade to a higher blackberry plan call MTN or your service provider" when you i try to call customer number 083 173 i get disconnected or got the error number does not exist. Now when i last spoke to a call center agent she explained to me that the bis service for R60 will last me 30days.
Now why am i recieving this notification about the 50% allowence?

MTN YOU RIPPING US OFF