Prophetic words. If I didn't know better I would think you wrote this comedy... or is it a tragedy?
I would suggest that it's lies somewhere in between. Nothing so inflammatory that it will run 10 pages nor so weak or unsubstantiated that another Dealer/Materials Provider won't take a cursory look see (and perhaps even be thankful for a 'heads-up', whether or not any other Dealer/Materials Provider chooses to go through all of the efforts to please this potential customer, as did the OP.....on both ends of this deal).
What seems true, with what we do know, is that the OP did exactly as he said he would prior to and throughout the initial part of the transaction, resolved the buyers concerns ASAP as we know isn't always the case with transaction's on BF, has a glowing recommendation from a prior customer which should trump speculative comments and lastly, has no obvious reason to try to disparage this customer outside of what some might attribute to the minimal amount of profit and effort realized by the OP when all was said and done.
I expect that the OP intended this thread to be more of a heads-up to other Dealer/Materials Providers. I'm sure that most all, if not everyone that owns a business and has so for more than several months, has had the same exact experience. Sure, it's part of doing business and as part of any community, be it our knife community or otherwise, is to be expected. But, so is leaning over the fence and informing your neighbor, or he to you, that 'Jack' up the street was recently involved in some untoward behavior towards an immediate neighbor. Again, nothing horrible, criminal nor dangerous, but just as a heads-up, nonetheless.
As a member of this community and perhaps as a neighbor in 'Jacks' community, I appreciate the friendly, transparent, not vengeful, informative, but not over-the-top bashing that is quite common on this and other forums. This was about as subtle and calmly presented as a complaint thread could possibly be with the stated intent only to warn one's community. All other accusations and/or assertions as to the OP's intent must either be due to lack of reading comprehensively or to simply satisfy one's own imagination as to how they expect the OP's description of the events likely 'really' occured.
We have the information we have. Until we have more, there's no valid reason to attempt to discredit nor discount the OP's feelings nor his account of the event. Further posts, that offer rebuttles by the customer or additional information presented by the OP, may change the entire landscape of this thread, but until then, I choose to accept the OP's information as it was presented. Simply.......as a heads-up that he's just recently dealt with a customer that perhaps no one (even as a seller who went through more hoops than many likely would in a concerted effort to help facilitate a smooth transaction) will be able to easily and totally satisfy (tell me they don't exist).