Pin faulty but it's not

I tried for a second time in a month to make purchases at Game Upington with Capitec. Everytime the teller teks me I punched the wrong pin. I checked and punched it in again and again like the previous time thier system it says wrong pin. The previous time I left without the goods I wanted. This time I said to the teller something is wrong, with a stupid smirk she just put her hand in the air. Again I left without my purchase. I will not buy at game again......has anyone else had the same Experience. Clearly by now they should Realize that many people is having the same issue.......