Jwyfk --
Oh boy, it just gets worse...

I am so sorry this happened to you...
Now you are finding evidence of more poor quality work and obviously no quality control..
Having used Optimum coatings on many vehicles including my own, I can tell you that none have ever required sanding, and all require a few weeks to fully cure.. This means they are completely dry from the bottom to the top when cured..
No one in their right mind, would have sanded off a coating that was barely dry and for sure not cured.. Do they have IR lights in their shop to speed up the curing process?
Yes, the best thing now is to call Optimum, you will have to tell them the name of the Shop so they can look them up and verify this shop is on their list of Authorized Sellers/Detailers of their Pro Line Coatings.. I just hope to heck these guys are on that list... If not, I don`t know how you will be able to get warranty work done from Optimum, however that works.. Good luck with this..
You have mentioned a couple of times, the Owner of the Shop not knowing how this all works when Coating a vehicle, etc... That should have been another warning, these guys are not good...
Next time you go looking for a Detailer, vett the heck out of him first... You need a list of people who had their vehicles coated last, pictures of their vehicles, their numbers so you can call them and ask them how it went, etc...
You need the Shop to show you in detail, pictures of all their work, coating or not...
Have them take you out to look at the shop... Is it clean? Is it all out of control?? Dirty? Do they have a lot of really good lights including many on stands that are used to see the sides, and tops of all the vehicle???
Look carefully at all vehicles in the shop getting worked on... Do they look good???
You need to ask them how many years, decades, etc., have they been in business....
Do they have and use a
Total Paint Thickness Meter??? Are they going to measure your vehicle BEFORE they work on it, and as they work on it???
Do you get a lot of eye contact from the one in charge?? Do you feel that he is on the level??
It is sad that pretty much anything I purchase anymore, I have to really get myself educated on the product,
before I make a purchase, because so many people are just liars and products are just junk copies of what used to be made in all the great places, like USA, Japan, Korea...
I have to know more about the stuff than they do, and once I do, I can very easily spot the misrepresentation, etc., that happens all the time..
I have been an Amazon Prime member for over 15 years, and long ago, there was nothing but great products on their website... Now, its flooded with the worst chinese knock off crapola I have ever seen...

One poor guy bought supposedly 6 NGK sparkplugs for his Acura.. Came in what looked like the correct NGK box.. 4 of the sparkplugs fit the engine just fine.. The last 2 needed the next BIGGER socket size to be able to install them!!!! Fake Chinese Knock Offs !!!! Its that bad sometimes...
Good luck with this!!!!
Dan F