Airtime disappears before is used

In these difficult times under lock-down MTN is preying on its own customers, I always used Mtn from the day I had my first phone now I'm more than 40 years of age. When you buy airtime it disappears before you use it, you can call any number they are not available, I'm now using other people phones. If there is someone who still cares about customers in MTN here is my number ***