Airtime dissappearing

I bought 200 air time 1 day ago. I have made 1 phone call of about 5 minutes, which should have been debited from the free time I received on the day of purchase. My air time is now progressively dissappearING. I use wifi and have deactivated my data on my phone so I know it is not data. But 1 day later I'm on R 45 balance. I have tried the 135 no and get to talk to a robot. I have also tried their online chat and got disconnected then had to go through an new person who asked me the same security questions even though they said they had read the previous comments. I am fed up. This is not the first time my data has dissappeared. The last amount of R120 didn't even last a day. Even though I made no calls.