Missing money

It would be interesting to hear Vodacom's explanation on the following:

I recharged with R 55.00 on 22 July ensuring my phone data, background apps and updates were off.

I made one call and before going to answer disconnected. I now had a balance of R 48.01. R 7 was gone. I received 4 calls during the day, checked my phone before bed and I now had a balance of R 41.01 - Another R 7.00 had gone missing. On waking I checked my balance and now had R 28.01 - R 14.00 overnight + R 14. 00 during the day 'used' without touching my phone. Magic that makes Voadcom rich and me poorer.

Your turn now Vodacom, lets all hear your version.