@Laura4680 If you haven't done so already, get your mattresses and box springs into bed bug encasements. Replace any mattress pads or foam type cushioning that you have on the beds, or put those also inside bed bug encasements. Doing this will ensure that if your guests strip the beds to check for bugs that they will see that you have taken proactive measures.
If you are pet friendly, you will want to treat for fleas. We "bug bomb" whenever we have a few days between guests, and we have an ozone machine that is run regularly. That seems to really keep down the spiders, gnats, no-see-ums and other insects that populate our mountains.
The bed bug complaint is a oft-used scam by guests. When we first started, we had at least one guest a season complain about bed bugs, especially after reports by local newspapers that such and such hotel chain had an issue. We knew it was a scam when one guest supplied pictures of their bites -- looking at the metadata of the picture, we found that it was taken off of a medical website.
Do you have a hot tub? When a hot tub is not chemically balanced, the guest can get a rash from it that can be mistaken for bug bites. We drain, clean, refill and treat our hot tubs between guests and have had no complaints since we began this practice.
Lastly, you can try posting a "Certificate" from your pest control company -- that might help.
I hope that you have no more complaints.