mac mini warranty support non existent?

Sorry to hear that.

If you have a friend or colleague with a newer Mac, you can use it to do a Firmware Recovery.

see > Mac computer status indicator light behavior - Apple Support

and > How to revive or restore Mac firmware - Apple Support

But a new Mac and use it to restore the broken one's firmware. Return the new Mac for a full cash refund under Apple's fourteen day return policy.

Maybe explain your plan to do that in advance, and perhaps they will reconsider the inadequacy of that policy. Or maybe they won't care. Either way it won't cost you anything.

You could try calling again as sometimes the reps may not "absorb" their training as well as others plus they are the first level of customer support. If you get the same response, request that you speak to a higher level rep.

It needs another Mac, as they said. What was their response when you asked if can send it to them?

Check to see if there is another AASP closer that can administer the Firmware Recovery.

Go to > Find Locations and click on Explore Service Locations.

You're welcome.