Was rear ended on the highway

Hello, yeah a lot has gone on. I have the truck back there are two supplemental’s that didn’t get fixed yet and you’ll give a estimate of $1059 to have the slide hitch repaired. On the trailer they estimated $8000 now to fix it. When they called to tell me that the parts were almost all In and they would let me know when all of them came in I asked her to send me what they were going to work on And fix. After reading what they were going to do. I sent a list of 10 more things that was clear in sight if they looked and if the adjuster wrote what he said he did. The service manager said he would write it up in The supplemental paperwork whatever that means. I did my best to check out what the bluebook was on my trailer. It’s a cougar fifth wheel 25 RKS and I see it between 17000 and 19000. I wonder what the diminished value is to it. I wonder if they would add the diminished value towards the cost of fixing it? And I’m sure it’s gonna be more money after they fix the items I told them that needed to be fixed. They said they already ordered the parts so I guess I’m kind of stuck . Having to have to get it fixed and not trying to get it totaled. Any ideas out there