****** of Airtime!!!

2 weeks ago I went to the Spar Liquor in Pinetown across Sanlam Centre to purchase Airtime and a buddy of Colddrink. The Cashier who was assisting me was an young dark lady who only gave me airtime worth R10 instead of the R15 I had requested, I realised this when I was in a taxi headed home, realising she might have made a mistake I kept quiet. On the 5th of March on a Saturday after 1pm I went back to the same store to purchase some stuff. Recognising the lady who had made a mistake with my airtime I told her my story and she rudely brushed me off and told me I might have lost the slip. I simply and calmly told her no that is not the case and again she was rude and didn't offer to investigate nor look up on the matter. The Security in charge saw what was going on and asked me if I was assisted and I adviced him that I wasn't assisted. The lady is dark skinned in complexion and middle sized. Customer service process wasn't followed and I still didn't get my 5rand of Mtn Airtime and this is bad service from Spar I am very disapointed and I want to be re-imbursed of my Airtime.