Mass Air Flow Sensor problems of the 2014 Nissan Altima

I purchsed this car Feb 2nd 2019 couple days later engine light comes on so car has 30day warranty so I call and they had me go there mechanic put in the shop. A code for 02 sensors came up but he say he just need replace Cadillac converter he didnt need replace sensors so 5 days later I pick up car and 3 days after light comes back on I call complain on way coming from another city hour away and noticing car jerking and loosing power on hwy on way mechanic car breaks down im stranded with baby for hour they tow they shop say it was fuel. Pumps I get car thinking things good I make a 300 paymemt since I still owed 1500 on down payment days later light comeson again smoke comes out back car when I start. It. In morning car jerks back real hard when I get on hwy or hesitate pick up speed engine making rattling noise and oil pressure sensor on I take it for 2nd opnion before taking back there mechanic and the thing they suppose fix still shows need be fix mass air flow sensor and then oil pressure sensor and spark plus so I tell mechanic did yall even fix mass flpw sensor cause same code pop up he says some times new parts can act faulty but dont worry we fix it. Got warranty but he gotta ask permission about spark plugs and oil pressure sensor so he ask me when I can come in I say Friday the night before my appt car breaks down 40 min. On hwy car looses power lights dont work head lighs dont work car key wont open doors or trunk and im getting I key system error I go replace battery that didnt help so Saturday they tow car and send me a repo letter since im behind payment cause im not gonna keep paying on car thats breaking down leaving me stranded at this point I gave them 3 tries so I just want my 1500 plus 300 back even tho warranty expired I did adress this 3 times before it expired.