Impossible Buyer!

[flyingmongoose6]

I write keyword rich titles for eBay listings here on Fiverr.
So a few days ago I got an order from a buyer, nothing unusual. I completed the gig and delivered. A few hours later the buyer messaged me and said that my titles apparently made his item go down in rank on search results. So we discussed back and forth and I tried to explain that more time is required to see exactly where the item will end up in search (eBay needs time to recataloge the listing). They can’t expect to see results in just a few hours. I of course was as nice as possible, but it just ended up with the buyer telling me that I didn’t know what I was doing. I’ve completed about 150 orders from this one gig, I have 99% feedback, and 75 reviews… this kind of thing has never happened before. We are no our second revision and the buyer keeps saying that the keywords “arn’t working out”. I’m out of keywords lol, what should I tell them???