COST ME 18 000 and still not fixed

I have a 1981 toyota land cruiser which is seen as a collectors item i have dedicated 5 years to rebuilding it to its original condition all that was left was the engine i took it to Kvb engineering and they promised they can handle such task they have now cost me 18 000 and ruined my engine. the service is horrid i as the client had to go and work on m,y own vehicle and to top it all off they still sent me a bill to rectify the issue they had caused.. please shut them down they rip people off