Mtn
Airtime debited without me using it

I loaded my cellphone with enough money on the 29th for my month end BIS deductions. The BIS month end R59.00 was deducted on the 31st. I still had -R30 airtime left. Without me making any calls, I got surprised on the 6th Feb, the balance is only R1. Have been trying to call 173 the whole day, but cant get through.

I need my airtime back.