Before you hand money to anyone, ask these.
First: what exactly does this fee cover, and what is still to pay? You should get a straight answer, not a total.
Second: what happens to my money if the visa is refused? The answer may be "nothing is refunded" — that is acceptable if it is said honestly and in advance.
Third: can I see the employer or the university directly? Legitimate placements have a real institution behind them that you can verify.
Fourth: who will I be speaking to, and how? If nobody can tell you, you will be chasing people later.
Fifth, and the one that matters most: what would make you turn my application down? An agency that has never refused anyone is not assessing anyone.
Taggedadviceagencies