Mtn prefers my airtime rather than data

I have been a mtn customer for many years. My first number I ever got, I still use today. <br> <br> I have noticed that my airtime runs out very quickly (Mtn you are more than we'll come to run a purchasing history on my number). I dialed *141#, ran a detailed balance and it all proved that my R60 airtime just purchased a few hours ago has evaporated without an outgoing call being made however my data balance was rather healthy. While trying to browse the net Mtn error page with insufficient funds kept popping up. <br> <br> I have loggers complaint on the Mtn site and tried calling them but the call literally go dropped on the three accasions. <br> <br> I am not much of a complainer, but just is extreamly unjust and crosses the line. I pay Mtn a contract fee every month and I buy data every month.<br> <br> Please contact me for other instances revolving around the same situation.