DX Group did not take my details, what now?

[juytu 0]

The 14th of April I had my interview at the US embassy in London and everything went fine. When I was sent to the DX group desk to take care of the delivery, I decided to pay over phone and not on the spot, while I only had cash on me and they don't except it. The girl at the desk did not ask me for the blue form that I was given earlier and told to give them, and now it's been 2 weeks and no one has contacted me. It is crucial I get my passport back because my job involves a lot of traveling.

I phoned up DX Group and got to talk to a rather non helpful girl who said I can't do anything without my tracking number and asked for my number and said the embassy would call me up shortly. No one has called and I wonder, who do I contact to get my passport back as soon as possible?

Thank you.