Baba the story confuse me. You mean say scammers or hackers fit access POS though receipts? If this one na true na him bi say them go don hack almost all the PoS for Naija. Receipt na wetin almost all POS operators dey issue to almost all customers.
I believe say your friend no talk the story well. Maybe the guy man see the password or him press something for the machine. Anyway, we need to dey careful because scammers no dey sleep, them dey bring no pattern almost everyday.
Na the obvious reason wey go make the guy want that amount of #100 airtime because em know say e nor go get the password once, so when the POS vendor dey try am, em go take note of am. But the receipt aspect sha still nor clear, because na means of confirmation say the transaction dey successful.