Carvana complaint: Engine is bad less then a year with car

I bought a 2012 Chevy Sonic on April 4th 2022 is now April 4,2023 and I can’t drive the car why because the engine is crap and Carvana refuses to fix it because instead of being 70,000 miles ot was at 72,000 this cars had issues since day 8 under the hood. I’m a single mother of 5 and they won’t fix the car because I’m over by 200.000 miles now that bs and this car needs to fixed or I need to start a law suit against you guys . Carvana won’t let me exchange the car because it doesn’t run but wants me to continue making payments on a vehicle that doesn’t work . I’m pissed and want a result a good one as well like a new engine for the car so I can drive it not just look at it . The owners of this company need to find answers for there customers because making people pay for a car that doesn’t work atvall and in less then a year of having it come on now .