I am suspicious about a user, what should I do

I would like to file a compliant about nathan bridenbaugh he bought an altimeter from my wife and I. He paid us through PayPal we thought things were fine. Time passed now he accusing us of fraud and saying the altimeter is full of sand. My wife used it the last time she jumped. I told him to send it back and I would refund his money, He returned the EMPTY packaging. I would like to warn other sellers on Dropzone to beware of him.
Thanks
Kevin & Jean

i just came across this....... and all i can say is WOW. Lets see, I bought an Alti-3 from you, and you said that it had a few minor scratches on it, but it worked fine. i paid $50-$80 bucks or so I dont remember exactly because I've bought so much gear over the last few years that its really hard to keep track, but this deal in particular was the only deal (while dealing with a skydiver) that i actually got taken. I recieved the Alti 3 in the mail and opened it to see immediately that it had sand in it ( between the glass and the dial) I emailed you and told you that i wasnt happy with it and you said "send it back and I will try to sell it, then refund you your money".
I told you that was shitty business ,and you should refund my money, and the shipping cost because you could have been honest in the first place and told me it was full of sand from probably sliding your landings into the desert or whatever. But I bit the bullet and sent it back, a month or so later i emailed you asking if you have my money for the refund, and you said that I mailed an empy package back and you werent refunding my money. So this is really amusing to me to see that you are "warning" other skydivers to be aware of me LMAO your obviously some sort of an idiot. Although, it has been quite a while since this has happened and i just stumbled upon it accidentally so im hoping that the time passing has made you realize how much of a slimy douche you have become ,and hopefully it has given you a chance to rise above this nonsense and if it has my Paypal is [email protected] for that refund...........................................Blue Skies (klembcke)
P.S. if our paths ever cross at a boogie or something ill be sure to throw you a lift ticket or two for the character building experience that you have given me.
Sincerely, Nathan Bridenbaugh