Theft and lies

I frequently use the goedemoed 7/11. Today I walked in to buy lotto tickets. I checked my wallet and counted 3 R20 notes. My bill was R34 so I handed the guy (named Rian I believe) what I thought was R40. He gave me change of a R6 in coins. When I opened my wallet to put the change in, I noticed I had given him all three of my R20 notes. When I asked him, he out right denied it but I know beyond any doubt that I had had R60 not R40 in my wallet. Disgusting!