Thank you southcoastpunter.
You did the right thing IMO. Being asked to bring any form of prepaid card/voucher is a red flag. It's got scam written all over it.
"I'm just going to the next room to check the balance on it"
2 minutes later...
"Sorry hun, there's no money on this"
Of course there isn't, her pimp has drained the funds. Doesn't take cash from first time customers. What a load of bollocks.