****** of airtime even with Int calling subscript

I am subscribed to the International calling **** with Vodacom. I have been charged the requisite R5. I recharged with R100 yesterday and bought data and was left with R41. I decided to call my mum in the UK knowing that the call rate is R1.79 per minute. Imagine my surprise then when I was cut off mid sentence after 8 minutes and my airtime balance showed 93 cents. I immediately called the call centre and was informed that they could see the recharge but the call and its details would take 4-24 hours to reflect so I would need to call back today and repeat my query. It is unacceptable that I need to constantly contact the call centre for something that is obviously not my fault. Someone needs to resolve this and RETURN my AIRTIME!!! I am fed up of having to constantly resort to complaining in a public forum to receive necessary action. How about providing ethical and transparent service the first time around! Is that so impossible!?