NHTSA Complaint #11652042 — 2017 AUDI Q7

My engine just failed after over a year of having to put oil in. The car has 77K miles and has been regularly maintained. Audi used this as a "demo car" and after purchase we immediately had to put oil in and were told verbally this is not an issue. The excessive engine oil consumption caused this catastrophic engine failure our an independent and trusted mechanic reports the engine has failed and cylinder number five only has 30 pounds of pressure. Please advise on what I can do with Audi for repair. We also have a 2019 and are fearful this will happen to that car as well. Thank you.