Did not receive prepaid electricity

On the 17.10.2017 at around 20:45 pm my mother purchased prepaid electricity from Lenasia Freeway BP a Pick n Pay express store. My mother requested R500 worth of electricity in R100. The machine only printed 1x R100 voucher and the other 4x R100 did not print. The cashier at the store Tshidi displayed surprise when the voucher didn't print. The store owner Hajira was called and she requested proof by means of a bank statement. The proof was sent through to her and upon calling and following up we were told that there is nothing she can do about it . This is causing a lot of inconvenience and its a week later and we still have no electricity voucher nor a return of the funds yet the statement shows that the money was banked by the store. We need this sorted out. Very disgruntled customer