stop eating my voice data!!!

I got an SMS at 4:30 PM saying that my data bundle had run out at 7 AM. So they had been eating into my voice data for 9.5 hours without telling me. Unacceptable. AS I HAVE SAID NUMEROUS TIMES BEFORE: TELL ME BEFORE the bundle runs out and WHEN it runs out. DO NOT TELL ME HOURS AFTER THE FACT.<br> <br> THANK YOU.<br> <br> If this happens again, I am porting to MTN as I have had enough.