Poor customer service

I have been using MTN network for the past 20 years. i have data contract with MTN of 40GB a month. the data in top up on the 17th of each month. On the month on June it was top up on the 17 but on the 22nd i was out of DATA i followed up the matter with MTN consultant up until today i am still waiting for the response. If i called i dont get any joy. I strictly use my DATA for social network only, it is impossible that i can finish 40GB in 5 days