2008 Subaru Outback needs engine

I bought a Subaru Putback and have nothing but
problems. In 5 months, I have put new tires on it, replaced
oil gaskets, timing belt, suspension rods, new steering
pump, new radiator, tune up with new spark plugs. Last
week, my son was driving it and it died. It had only 0.5 qts
of oil. I had oil change done June 1st and that place
showed me video that they actually put oil in it. They
blame the oil gasket repair for not fixing the piston seals
and causing the lower engine to fail due to compression.
3 other mechanics said there is no way that they put oil on
it, because in 1 month it burned through 4 qts.

I don’t think I have any recourse and I think I should dump
this POS and never touch Subaru brand again. Any
thoughts? If I put another $4K into it (engine with 130K
miles) then I am putting another Subaru engine into it.