JubJub,
Mate as "dnej" said the repair could cost in the range of $4000+ to do proper..do you think the boat yard is really going to spend that type of money to fix it the right way.
They have already proven themselves to be liars.. just walk away..the right boat will turn up for you..even if you bought it just to have a boat and then it falls to bits, you will be in the same situation as now with no boat ..and poorer.
Hope you find a good one soon.
Tony