Missing Airtime

I recently upgraded my contracts and was told that I needed to a SIM swap as the SIM card I had cannot be cut. I asked the sales consultant what will happen to my airtime that I have on both my contracts and they said nothing will happen to it and it will be transferred to the new SIM. After the SIM cards became active the airtime was there and the following day the airtime was gone on both SIM cards. The total amount of airtime that has gone missing is R800. I phoned the branch and asked for assistance and they had told me that they will log a complaint to the Head Office for investigation. I had to phone to get feedback only to be told that it was possibly due to internet usage but I only use my phones for Whatsapp and phone calls. To this day they are unable to give me feedback and I would like to know how Autopage is going to refund me for the money that has gone missing from my account. Please sort this out today as this is poor service from Autopage and I am considering cancelling my contract with them.