Need a one-time Phnon Penh process server--ideas? (Phnom Penh)

We're looking for someone to serve legal papers to a person living in Phnom Penh. It's just a one-time gig, but we will pay $150 via electronic funds transfer or Paypal (whichever is easiest). There are professional services in the city for this type of work, but given the amount of money we have lost already, we can't afford them.

Any ideas where we might look for someone who would be willing to do this within our budget?

The job involves two steps: dropping off the papers with the person, and then sending us a notarized affidavit that the person has been given the papers. There are several notaries in Phnom Penh, but I know the US embassy provides this service for citizens.

All suggestions extremely welcome! Thanks so much for reading.