oil pressure,Check engine light refuses to go off after engine replaced

My check engine light has been on since 2014. I'll try to make the story short. In 2014 my oil light and check engine light came on. Got the oil changed & took car to dealer for engine light. They said no oil was in the car & that the other place probably didn't change it. They put oil in the car & reset the lights. About a week later lights back on. That same week engine locks. Tow the car to the dealer. They say engine needs to be replaced due to sludge. They blame me & say I didn't do enough oil changes. I need my car so no time to argue. I get the engine replace