I'm gonna play the other side of this..
You bought a used boat PRIVATELY???.. took it to a dealer trying to get warrantee work and they told you that you weren't covered? It sat in their yard the entire time that you tried to straighten that out privately and then you came back in proving your were covered and then they did the work under warrantee?
I'm surprised they didn't add storage to your bill as well.
As for the friction lock... were you SPECIFIC at what you wanted installed? If so you have grounds to have the item they installed removed at their cost, not yours. If you just said you wanted a friction lock, they probably tried to sell you the cheapest thing they had in stock (or maybe the most expensive - I don't know the shop). As for it not working properly or clearing items.. that is THEIR issue to fix.
The top... an act of god my friend, absolutely not their responsibility. Not sure why your top ripped. GBFisher's as well as my own Lund have been out in some pretty nasty snow coverings, GB's especially, and our tops are still going strong after many years.