MTN Disappointing to say the least

My phone is activated for roaming and yet each time I travel it doesn't work. I have been to 3 MTN stores and the best they can tell me is that I must call the call centre before each trip to make sure roaming is also activated on the network. As it turns out it is activated on the network and it has been escalated. Result no change. I have been a client for over 20 years and the only reason I havent changed service provider is because I don't think anyone else is any better.