When going through your issues, have realised a few subjects. 1. You haven't mention the make of the car. 2. Model/year of the car. 3. What was the report on car max and what was your concern.

Next, break pads, break drum, etc are the easily burnout parts of any automobile. And its all depends your usage. If you are rash driver/ frequent braking - no sense in it. More than that, the parts cost less compared to other major issues on a vehicle.

Its complaining after 4 months. That means, no other issues on this vehicle rather than the wear and tear parts.

Regarding the sister, have heard about this guy. He is a cheater. Don't believe him. He will not give you his ID/ License. Say my sisters vehicle. He is a cheat. Act as arrogant. Because his intention is wrong.

Note: Always check with the company service centre regarding the chekups. They can help you a lot on check-up than the unknown car experts. Must ask the persons ID copy even its his car or his friends car or sisters car. Its your right.