Airtme dissapearance

I RECHARGED MY CELL ON FRIDAY AND ON SUNDAY I CONNECTED FOR FEW MINUTES ON THE NET BUT IN THE AFTERNOON WHEN I QANTED TO CONNECT AGAIN IT GAVE ME SMS ABOUT FREE AIRTIME AND DATA WHEN I CHECK MY BALANCE MY AIRTIME WAS GONE. WHEN I CALL THE CALL CENTRE ON SUNDAY THEY TOLD ME TO CALL AGAIN LATER WHICH I DID BUT GOT NO EXPLANATION AND QAS TOLD TO CALL AGAIN MONDAY WHICH I DID BUT TO BE TOLD MY AIRTIME AND BUNDLES WAS USED UP BY INTERNET THAT QAS CONNECTED THE WHOLE DAY. QUESTION HOW WHEN MY CELL WAS OFF WHEN I WENT TO CHURCH? HOW WHEN DATA COMMUNICATION WAS OFF?AM NOT STUPID I DID IT AND HAVE BEEN USING THIS HANDSET FOR MONTGS AND UNDERSTAND IT. I WANT MY AIRTIME NO EXCUAES. THIS IS NOT TTHE WAY TO TREAT CUSTOMERS OR IS IT WITH THE TELECOMMUNICATION INDUSTRY JUST BECAUSE PEOJOPLE HAVE ACCESS TO THE SYSTEM THEY CAN JUST TEMPER WITH IT AND TAKE PEOPLES AIRTIMES?