Thanks for your question.
How can you establish your claim? Do you have anything in writing to establish that the neighbour would pay the agent and then agent pay you. Without anything in writing it will be difficult to prove.
If you can establish the claim then you can claim online at moneyclaimonline.com. You will need to pay a fee upfront, but you can claim this back as part of the claim. Only really worth doing if you have a good case because if the claim is refused or the other party wins you will end up out of pocket.
Sorry hit send before I was finished.
If you have any questions or queries please let me know.
Happy to help further.