Need answer fast: partial refund on eBay, and the sales tax

I am negotiating a partial refund from a seller who made a mistake in their listing, so that the item I got was not what I thought I was buying. I am still interested in it, but it is worth less than I paid.

My purchase price, of course, included sales tax, and the amount is material. The amount of the partial refund I will ask depends on the answer to my question below.

My question: if the seller provides a partial refund, does eBay automatically also refund the sales tax for that amount, or do I receive only the refunded amount without sales tax?