It is unfortunate people almost have to do this, but that is what I did.
I also have already taken after photos of each rim as a whole like you stated and the damage is very visible, unlike the before's
im talking about photos from the same distance and perspective as the before. they claimed that your before photos were not good enough to determine any prior damage that could have been present, but taking photos from the same angle and distance will help prove your point and get the wheels repaired.
although i wouldn't get so into this trying to make them literally buy new wheels. the only reason anybody would buy a new wheel would be if the damage was too great to repair to oem quality.
the same thing in terms of bodywork, you can't tell an insurance company that you want your entire hood replaced because somebody put a dent in it, if it can be repaired for cheaper then that will probably be the route gone.
for wheels like those, it would be fairly cheap compared to new wheels to just have them refinished to oem spec. the people who are saying they should buy you new wheels probably don't know too much about wheel or body repair, and having them do that just wont happen.
the best bet would be the pictures from the proper distance and angle, speak to the owner of the shop, and explain in detail why you are so upset about it. and tell them that you are allowing them to handle the situation before you take it to small claims court.
if you appear before a judge they will most likely rule in your favor if you have all your ducks in a row, ie, pictures of before and after like stated, previous pictures and/or articles from the forum from previous weeks or months showing how meticulous the care for the wheels and car was. and some quotes from different wheel repair shops stating the price to bring them back to oem quality.
the best the shop would be able to do would be to deny what was happening. but it would probably difficult for them to take that route and wouldn't benefit them with all the evidence.
just have to be firm. i had to literally come back to the place that ruined my wheels finish 5 different times to get them to get it right. and each time they either said they didn't do it, or that the wheels were already junk, etc etc, until you trap them in a corner with their own words.