So....this one eats me alive

[Cujo#31]

About 3 weeks ago?? I had posted the need to move a sweet mature Chevron. It had been in my display for near 6 months at this point. I was able to trap the fish, and move it to my empty quarantine tank. The tank was empty prior to adding the fish, so I filled the tank with display water as I needed to do a water change anyhow. 2 days after putting Chevron into the tank, the buyer picked the fish up,
2 days after this the buyer notices some white spots on the fish. I was shocked because not only did the fish look healthy to me, but so did (and do still) the fish that shared my display with the Chevron. The Chevron apparently has anchor worms. I have offered to take the fish back, I have offered the buyer a full refund, and I have offered anything else I can possibly offer to make this right, however the buyer’s response has been best described as “the sound of crickets”
Anybody that knows me, or anyone who has done “business “ with me knows I am a man of my word, and I will stand on my head to keep everything above the board and I have worked very hard to not be “one of those guys”. So I put it out to all of you, my peers, pull no punches, please. U have tried to contact the buyer quite a few times with no luck. Am I a fool for pursuing this any further? Have I become “that guy”? Sorry, this one really bothers me. I would never knowingly EVER do something to harm another reefer’s tank or livestock. Certainly not for the sake of a few dollars.