If you suspect fraud, write to:
1. Your State's Attorney general.
2. The dispute department of your credit card company.

Document what you just told us.
Provide details (times, dates, names of who you spoke to, copies of
orders, etc.)

Say in the letter to your ccard company (copy the vendor & the AG)
"The vendor has failed to fulfill his side of the purchase contract
(document this)"
"I have made a good faith effort to resolve the issue with the vendor
(document this)"
"The vendor has failed to act in good faith (document this)"
"Therefore, I dispute charges on date [xxx] from vendor [xxx] in the
amount of [xxx]"

Sign and date.
Use certified mail if you want a record of it, but you don't need to.

If these things are true and you have documentation to back them up,
you should have no problem. Assuming that you acted within your ccard
company's time window.

Typically ccard company says "OK, you said he ripped you off; we
believe you; here's the money back and we won't pay him. Hope you
didn't lie, because then you committed fraud. We're not involved; just
doing what you told us to do."

Within the time limit, it's no risk to the ccard company because they
haven't paid him yet.

Did you use paypal? Pay by check? Very little recourse here, and now
you know WHY the vendor won't take a ccard!