Spar bellville

Buying pre paid electricity from Spar Bellville: Request R300 , get R3008 with 1267 units. Try to correct cashier , get told of that it is correct. Chat to my colleague in the shop who agrees that something is wrong , back to cashier , still get told off that it is correct. After some time the cashier asks help at her colleagues who also tells her that she has made an big error. No apology , no customer service , only attitude. I have now been penalized for buying too much electricity due to a *********** cashier with a bad attitude. Now R300 only gives me 117 units. No use explaining this to the same cashier , only attitude , no customer service.