Call limit

I've been with MTN for 15 years now. I upgraded a month ago and made it VERY clear that my contract must either remain the same or made MUCH bigger. I specifically said "I want to phone as much as I like without a limit". It was agreed. I pay R 2'100 for this contract and I'm HAPPY to do so because I've always paid so much. Its now the 10th of the month and I don't have "airtime". Reminds me of my days when I was a student. I am extremely irritated. I'm running big projects and need to phone when I need to phone. Anytime, anywhere, without limits. Please fix ASAP