Quoted from Markharris2000:OP... be careful! The credit card company will TELL you what to do and they will likely need you to ship the unit back to seller to regardless of his current situation or finances or hardships or COVID whatever. The Visa or Mastercard merchant agreement is very specific in the remedies they will seek from the seller, but for YOU, the buyer, you are protected by YOUR agreement that you signed when applying for the credit card originally. In a nutshell, your contract agreement signed by you when you got your credit card says: if you receive goods or services that are materially different than what you contracted for, their buyer protection kicks in. That said, the CC will tell you what they need you to do to complete your obligation in this dispute.
(I've been through more than 2 dozen disputes vith VISA for all kinds of goods and services, and the credit card company ALWAYS makes it right AS LONG AS you do your part of what they ask. They will likely want proof that you shipped it back to him).
I suspect that the reason he shipped it to HEP is to get an "outside expert" evaluation for the CC company.
In my one CC dispute, I had to do that. They wanted an evaluation to see that the service I received was "below industry standard". I got a letter from a secondary provider which said basically "Yes, we would never provide service that looks like this and would not expect a customer to be satisfied with it."
Once the CC got that statement, they credited me the full amount.