Advertising on Facebook Question...?

[Who]

"Anyone got any advise, please make it positive? "
Its a bit stupid to say this , cos all you are saying is - say things that will make me feel better/calmer

"What should i do if it goes wrong?"
There s nothing you can do
If its going to go wrong it already has
If the person you sent the money to is dishonest -
you have sent them the money,and there is no way you can get it back
They have withdrawn it from their account
You wont see whatever it is they are supposed to be selling.
You will never hear from them again
There is no way you can trace them.

The only thing for you to do is hope they are honest.