Some of those would probably come off with a Magic Eraser. But since the ad said excellent+ rather than New, the seller has some wiggle room. I hope you sent it back with tracking info.
I am sending it back after work today.
The seller did say it was excellen+ in the text of the ad.
But under "Item condition:", it says "New other (see details)"
And ebay defines New other as "A new, unused item with absolutely no signs of wear. The item may be missing the original packaging, or in the original packaging but not sealed. The item may be a factory second or a new, unused item with defects. See the seller's listing for full details and description of any imperfections."
So I was expecting that it didn't have the original packaging or something. And the text of the ad never mentioned the stains or ding. Like I said, even after I sent the pictures, he said that he found nothing wrong with the bass before he sent it.
So I don't know if he really believes that he sent it out perfect or he is just outright lying.