Help with soaker tub ReInstall?

http://www.proflo.com/proflo/showRecordDetail.do?R...

The bathtub has always sagged when filled with water and the caulking tore away and we always replaced it and put some bathtub trim around it to stop with water leaks. I recently ripped up all of the bathroom tile and removed all of the bathtub caulking. Well, one of the tiles on the bath deck was loose so I pried it up to replace it and I kind of got carried away and I pried off the whole front skirt. The sheetrock was nailed in and not screwed in, so it all came off in one big sheet of sheetrock and tile! Anyways, I found the installation instructions underneath the tub and read them and yeah, it was totally done wrong. It is supposed to be set on a mortar bed, and right now it only is set on some old scrap wood (with old bend nails still in it) with broken shims to make it level. So I want to know how to make this better. Can I jack up the tub and put a mortar bed in to do it right? Also, there is nothing supporting the lip of the tub back against the corner wall.

Also, we bought the house new and fought the builder for several months to get answers as to why the tub was sagging. Now that I have proof do you think he will agree to pay for repairs?