Happens to us all. The difference is how well you recover from it. Why I actually love Credit Cards. You get the item and it's fake, damaged, or not what they say it is. You just send it back, demand a refund, and if they refuse call your Credit Card company and dispute the charge. Recently an Auction House claimed a sword blade was etched but hard to tell from the photos. Being me I bid the lowest and won. When I got it the blade was cast and a fake/repro but the handle/grip was original. Contacted them, sent it back, and they refunded me.
Had a well known Dealer I brought many items from, he has even been mentioned on this website awhile back. Got a Rev War musket from him but closer examination after I got it, it had 2 small letters that when researched it was a Gunsmith that was in business right after the Rev War. I kept quiet, and months later he had another Rev War musket I really wanted and I knew was 100% legit. Traded the one I had back to him and gave him like $500 more. He put it back up on his website and sold it months later.
On bayonets I had a hard time finding ones to fit my Rev War muskets. After getting 2-3 that did not fit I took the musket to a show and the 3rd to last table found one that fit perfectly. Traded all of them to him for that one and to sweeten the deal I think I gave him $50. I was happy even at a slight loss. I still have 1 period bayonet in my closet that didn't fit, any takers on it?