Showed up at meeting with less than agreed to funds, and has failed to make good

kimber750 agreed to buy a Taurus 24/7 .45 including holster and ammo for $300.00 When it came time to close the deal, he was $50.00 short. I decided to trust him, gave him the merchandise, and he promised to send me a certified check the next day. It has now been over a week, no check has arrived, and the one time I was able to get through to him on the phone, he promised to transfer the money to my pay pal account. That was two days ago, and has not been done. He no longer answers his phone, but I left him a message offering to meet him again, and either complete the deal, or refund his money and take the gun back. He has not responded. This is the first time i have had a negative experience with a member here, and hope your involvement will bring it to a satisfactory conclusion.
Thank you, Keith Marion