Mtn are a bunch of *******

I am utterly flabbergasted at mtn. Mtn hadn't sent me my invoice last month. I called and complained many times. I eventually did receive my tax invoice but got billed R18.86 for it!!!!! I am in shock. How dare mtn bill me for something that was there fault namely for not sending me my invoice timeosly. Mtn do the right thing and reverse these ridiculous charges. Shocking bunch of *******!!!!!!!