Well thats interesting hey that they are back up.
2 suggestions.
1. you could message from another number and get there early so you can spot them and get a rego number and a few photo's
2. you could call up and see if she would do a fantasy of you paying her for sex and then another guy turning up and taking off with the money lol. Sorry just joking. You could have 3 or so mates waiting for them and all 3 film and photo and then take it to the cops. Follow them home and see how you go?