I have been looking at used trap guns, anything break action, over/under, undersingles. I have a little bit and I know I have to spend some to get something good. I recently located a nice SKB in Texas for a nice price, the person who had it refused to sell it unless I used one of the payment apps that have no recourse once paid. I have been unable to get this guy away from that. I want to buy this gun from him but he refuses to go anywhere else. All I can say is buyer beware.
I would definitely stay away from sellers like that - unless you use a proxy like an FFL to confirm the goods and shipping (from FFL) once payment is sent/received. Just not worth it as it is most likely a scam.