Going into a Potentially Fraud-Bait Line of Business - Need Advice

I've just gotten into a completely new and separate line of business, specifically selling pre-owned luxury goods over the internet. So far it's been a lot more successful than I hoped it would be during the first 4 months of operation within a small market (forums and specialty e-commerce sites). Now I'm looking to expand to Ebay, a much bigger market.



My concerns here are around fraud. The items I am selling can be easily resold at pawnshops and similar venues, so it's my concern that these types of goods will attract fraudsters and scammers who will buy and steal my goods through credit card and paypal shenanigans.



I need advice on how to navigate around these shark-infested waters and protect myself. I have been selling on Ebay for almost 10 years now with, but these have been specialty goods of my own manufacture that have a limited market so there was a low chance of scammers. So I've been around the block.



One thing I have done is to insist on a signed contract of sale for every item I sell for this new "pre-owned luxury goods" business. This way if any paypal or credit card shenanigans happen, I have enough paperwork to fight it, or worse case scenario to sic a debt collector at them. Not sure if this is enough.



Please no "don't do it" responses. This is not an option.