Bad Customer Service

I called MTN customer service today to ask about my missing airtime. What a rude customer service consultant I spoke to ! I'm appalled by her response and I wouldn't want to call the line again. To top her rude response she put the phone aside and possibly left while I was still talking with her trying to understand what went wrong. I held on the line for 22 minutes until the call was dropped I'm not sure whether by her or automatically since she wasn't talking to me. I'm still unsure what happened to my airtime. For MTN would keep such behaviour in their customer service desk is just out of this world.