[MIPS]

Because I cannot understand your story due to its complete lack of paragraphing:

-You bought a radio
-The radio shipped
-The radio is suddenly "lost" and you are offered either a refund or a substitute
-They ask you to reply by email, which ebay straight-up says never to do.
-You get your refund
-A period of time later you get something from the seller which is CLEARLY not what you ordered
-Even though you got your money back you pester him anyways, he gives you a BS excuse which frankly I don't understand and offers to accept a bribe in exchange for positive feedback.

I'm not sure what the bait and switch here is. He didn't ask for more money once it was "lost", you got your refund, sure you got something (even if it wasn't what you wanted) after you got your money back and at that point the case was already closed on ebay's end so you had no obligation to reimburse.

Edited: okay, so it seems they listed one radio and were intent on shipping you two junk radios and tried to use lost shipping as an excuse to bamboozle you, but for whatever space-brained reason they gave you the option to refund, you opted for that and it backfired and you got two free radios. I wouldn't be doing business with that seller again. Just ignore their further messages and move on.

Edited: Let me reread this again.