Turned away to purchase electricity with my RCS card

I went to purchase electricity today, waited in long queues to get in, only to be told by Maria when I got to the till that I could not purchase electricity with my RCS card, yet I do this every month. RCS has even sent me a message to say I can purchase electricity at any Pick n Pay, Spar or Checkers.

This is really bad service and especially during lockdown when you only go out when necessary