TELKOM PREPAID BAD SERVICE PROVIDER.

I find Telkom prepaid service is not delivering an honest to me. I'm with Telkom for more than 5 years and more and use their prepaid product for my mobile phone. Question - Whenever I load my prepaid DATA and VOICE to all network and have some balance money left on my phone i find that they deduct my money for whatever reason. This deduction happens while I have enough DATA and VOICE to all network still on my phone. Is this a normal action from TELKOM or is there a reason why the take my money. I query this with their customer service but they cant give me a reason. They always blame the fact that sometimes I'm out of Telkom network range of which I cant see why they should take my money. In general TELKOM service is BAD and the same go to their NETWORK range even though they suppose to be the oldest service provider in the country. My question is simply ...WHY ARE YOU DEDUCTING MY MONEY FROM MY FROM MY PHONE.?