A couple years ago I got a white tail done by one of the better local guys, at the time he was $650 while everyone else was $550 and it was a 2 year wait. My buddy couldn't figure out why I didn't go to the $400 guy that got them done in 10 months.
Not to insult your deer, but thats about what the $400 deer looked like.
I'm thinking you can try to get that guy to fix it, but I dunno if he's capable.
1)The 3 options I see are take it back and see if he can tune it up, but temper your expectations
2)If the deer has sentimental value and you really want something quality out of it, give up on this guy, take it to another taxidermist and see if he can salvage it, and maybe be prepared to buy another cape
3) if you can't stand to look at it, take a picture, take the horns out, mount them on a plaque, throw the rest away, frame the picture and hang it next to the horns and chock it up as a lesson learned.
Its not great and its not terrible. Just depends on what a guy personally wants to feel when you look at it.