Explanation please!

I have a lot of airtime just disappearing off my phone that I've been accumulating over the past year actually on my top up package, I never have to top up my airtime, but from having in the 400 airtime, I now have R44, after purchasing R180 ... this is absolutely not the usage of my phone, because the usage of my phone hasn't't changed either when I'm trying to save. I want all my airtime back, and check my records of what airtime I have left by the time I receive my next month's package!!!!!! Pathetic service by your company