As both a frequent seller and buyer on ebay I don't recognize the situations reported by OP. If power seller, then no way funds would be withheld. That is only for new sellers. So I never heard of being unable to leave feedback. Of course if transaction reversed, then right to leave feedback may end. This all sounds fishy. Not saying OP is wrong at all. Just there is some disconnect here.

I get so much good merchandise and great service at terrific prices on ebay. I couldn't afford to ride nice bikes without ebay. I'm sorry OP is not having the same experience.