I used to do business like this with people from my prior MO and I was blunt from the start. It saved me from dealing with a lot of BS and I hope you can benefit from these words.
You tell them you are not waiting, that you want to do any trades right here, right now. If they want to hop around on other accounts or pay you back later. Don't even bother. Don't don't believe "can I borrow?" statements because those are often scammers. And for GF, do all your business with gold or item trade. Not AP. Because that is often a scam. There is a reason you're only able to use one method of payment per account for AP. And that you can only purchase AP once a week I believe.
All I can tell you, is you cannot trust anyone on this game.
And the words of the people you come into contact with.
UltimateMen, is a noob. Sounds like he was in on the deal to be honest. Since he told you that she wasn't a scammer to begin with. It's very common for the second party to comfort you and lie, claming they were also scammed by the same person.
I adivse you to add both of these people to your blocked list. Your gold won't be returned to you unfortunately... especially since you have no legitimate proof. Screenshots are very important if you feel you might be set up. Get into a routine of snapping screenshots with the trades you do here on out.
Oh yeah, and just because someone might be popular on a sever, doesn't mean that they are honest, legitimate people. Even some of those well known players are playing with negative intent when the opportunity arises.