Buyer is refusing to accept proposal and put money in escrow, stating that his boss will contact and pay me"in line of our conversation". What should I do?

I've bid on a project around two weeks ago, after a weeks time the seller of the project contacted me that he would like to work with me. We discussed the details, he told me everything about the project and how he imagined the results., The project was about a presentation advertising a party gifting service. After a few days of discussion we agreed that I will start the project, whoever I realized that he didn't accept my proposal yet, so I was working "free" if that makes any sense. I am new to the site but I have read through the policy and I am aware that a proposal needs to be accepted and the amount sent to the escrow before the work starts. So I started to work on the project and asked him to accept my proposal because it was still pending and I was afraid what if I send him the final work and I won't get the money after. He refused to accept my proposal, despite I have explained several times that this is the policy and we should follow accordingly. he kept rushing me by sending messages that he is waiting for the project, however I have asked him several times about the deadline and he said nothing about any. Now that the project is done I refused to send it to him unless he accepts my proposal. I said after that I can send the work for a preview. He is messaging me saying that he has no money on his card and his boss will pay me later. I thought I should report it because at that point I am clueless what to do.