Money ****** by pep store

I deposited money into the pep money card, or rather bought a money voucher to load into the card for my elderly mother, when I arrived at home do loaf it, the voucher had already been used, I reported this to pep and was asked for details, I sent the details n was promised a return call on the matter, instead no call was received, when I reported it again I was told I could not be reached, I'm not sure if pep is running a *****ing **** or what.