Pay the Charge
There are a few things that make this scam believable, and most of them are down to simple chance. Had this person not gone on vacation, or if she’d had her phone switched on, then the sister would’ve avoided paying the $900 “fine” entirety. Sadly, luck was working against her!

Whatsmore, it’s quite creepy that the scammers managed to get the user’s details and find the sister’s number in the first place. That’s one dedicated scammer! Just remember that anyone asking for money over the phone is unlikely to be real. The police would contact you in person if it were real.