how do you know this do you get some one with borescope to see what was going on , did you do a compression test ,
10 hours labor with the engine out , that taking Micky , i love to open up your engine and see what they have done , lot of the Mitsubishi blocks that were made for marine use or plant use use metal gaskets , they can be reused ,
but my advice, anyone that has an internal engine problem get looked at with a borescope can save a lot of money a messing around , do you only have a tiny engine bay ? you can change the rings with out removing pistons , its not a big job , i find it hard to believe all of the rings were gone did they give you back your engine bits top prove they had actually changed them ? i would advise anyone to do this .