FNB App Prepaid Electricity

I bought prepaid electricity from the FNB online App on the 2 November 2019 and received 651 units for a R1000 and bought again on 29 Novemebr 2019 for a R1000 and only received 404 units which is clearly not right... This needs to be investigated as I believe I was **********, FNB only rep**** and said that I need to phone Eskom as it's them but in fact I buy it through my App every month...