What would you do?

So, I have this vintage dress listed that a particular user has been lowballing me on for several days. We went back and forth a few times (them in $1 increments —which really chaps my you-know-what) until I hit my bottom offer, which they countered again with $1 more than their last offer. At that point, I decided to decline and block because this particular user has done this to me before on some of my other vintage dresses and I’m just over it.

About an hour later, another user appeared and liked the item and made a low offer. I countered and they went up $1 — in hindsight, I SHOULD have probably been suspicious, but my closet has been pretty active this weekend, so I countered with my lowest again, thinking nothing of it — and this time they accepted.

At that point I checked the profiles — same city and state, and the shipping label generated has the first name of the username I blocked. It’s the same user. Should I cancel and block or just ship it? It’s posh, so if they decide to leave a spiteful 1 star rating, no one will see it, but I really just don’t want the aggravation….