DATA NO REFLECTING

I HAD LOADED AIRTIME AND CONVERTED IT INTO DATA AND IT DIDN'T REFLECT IN MY ACCOUNT. I CONTACTED THE CALL CENTRE AND THEY SAID THAT THE SYSTEMS WAS DOWN AND THAT ONCE THE CONNECTION WAS RESTORED IT SHOULD REFLECT. FOR THE PERIOD WHERE THE SYSTEMS WERE OFF I COULD NOT RECEIVE WHATSAPPS OR EVEN REFRESH FACEBOOK OR INSTAGRAM. ONCE I STARTED RECEIVING MY NOTIFICATIONS AGAIN I THEN CONTACTED THE CALL CENTRE AGAIN AND I WAS TOLD MY DATA GOT USED VIA INTERNET, HOW CAN MY DATA BE USED IF I HAD NO INTERNET CONNECTION AT ALL? I COULD ONLY MAKE CALLS. I FIND THIS VERY STRANGE AND UNACCEPTABLE. MTN SERIOUSLY NEEDS TO WORK ON SERVICE DELIVERY NOT TO MENTION THE SIGNAL PROBLEMS.