Is this the one you are referring to? If so, at least the guy was being honest. Kudos to
ebay if they are the ones who removed the listing. Although I suspect it was the lister. Likely did it out of pure frustration.

The seller writes:
Unfortunately I purchased a US revenue collection from a dealer selling Baron Frederick von Lubcke stamps and collections. The BARON is from PARIS and he supposedly built a huge collection with huge purchases.
The key stamp in the BARONs collection turned out to be FAKE FAKE FAKE! It was supposed to be genuine! The way that I found out it was FAKE was by sending a picture to a certification service to see if they would certify the R84A and how much it would cost.
The reply from the certification service was "Don't waste your time and money on certification. This stamp is not genuine and we would only certify it as a fake. The perforations have been trimmed off and the date cancelled is incorrect for this issue."
The catalog value of the BARON collection I purchased was 20k, and the key stamp in the collection was this R84A described as 'the very scarce R84A' with a catalog value of 10k. I paid 4,000 for the collection. Therefore my cost of this R84A was 2,000; it was supposed to be genuine.
Unfortunately I was drawn in by the allure of the whole Baron stamp story which you can probably read elsewhere.
Such incredible stories as: " This is from a Barons estate in Paris France. I have been working with this estate as many of my regular customers know for over a decade. I go to Paris several times a years and I am accompanied by the grandson to a very old Paris bank and vault where the grandson selects sealed envelopes and gives to me to sell in the US. His grandfather started collecting stamps in the late 19th century and his son also added to the enormous holding."
Needless to say I surprised that this Baron collection contained this FAKE stamp and it was the key item in the collection I bought for 4K. So I contacted the dealer to explain what happened and to see if I could get some type of credit or exchange. This stamp dealer has been in the stamp business for 50 years, runs a stamp foundation, has been a stamp appraiser for a long time, and has even written a book to help collectors. I thought I would get fair treatment from a longtime dealer.
However I was VERY SURPRISED at the reaction of this dealer.... In reply to my email, I got many nasty emails back, such as "This is all BS" and "I do not have expertise in this area" and "You remind me of a friend who bought a stock for a few thousand bucks held it for 5 years, turned out the company was no good, sued the company (after 5 years) about the same story as yours."
So the dealer would not do anything for me except offer a 10-20 percent discount on a future purchase from their highly over-priced stamps that already have a best offer option. He even said to "please send the stamp back" which was only an attempt to immediately confiscate the stamp (evidence of fraud).
The bottom line is I have lost $2,000 and the dealer does not stand behind their stamps after they are sold.
I thought possibly someone might be interested in this FAKE STAMP and this story. The provenance of this FAKE STAMP is fantastic....... this is from the famous Baron Frederick von Lubcke collection, a BARON in PARIS.
I doubt this FAKE STAMP will sell but I lowered the price to 1,900.
Finally I hope your stamp collecting experiences are always good and you always enjoy stamp collecting. For me this purchase and the dealer's response has been a real turn-off to stamp collecting.... which is a hobby I used to enjoy. Please be careful with your stamp purchases,try to avoid buying stamps from unscrupulous dealers.
Thank you.