Thumping noise when I'm hitting the brake

I understand the skepticism of some people here. But I’m gonna explain a bit more why I’m willing to give this shop the benefit of the doubt.

I bought this vehicle from a dealership about 2 months ago. The next day after i purchased it, I brought the car to this shop for an oil change. I asked them to do a quick inspection. They did that and they lifted the car and spent about 20 minutes or so inspecting things. They also did one of those computer diagnose thing. They gave me a list of the issues (oil leaking/steering wheel etc) with the car, knowing full well that I wouldn’t be doing any of these fixes at their shop. They knew I would be bringing the car back to the dealership to fix the issues. I only paid for the oil change, no charge for the inspection.

I came back for the second time to this shop because one of the issues (car hard to start after refueling) was unresolved by the dealership (brought it to them 4 times) and local mechanic by my house was not able to figure out the problem. Here’s a thread I made a while ago [SOLVED] Code P0455 - Car is hard to start after filling up gas tank . They spent about half an hour or so and they charged me $150 + tax which I thought was reasonable. They also verified the fixes made by the dealership (steering wheel/leaking)

The third time I brought the car when I noticed the car started making this thumping noise. They drove it a few blocks with me. Everything feels good to them. They told me the brake is good, the car runs good etc. and they lifted the car and told me the rotor is rusted and probably that’s what causing the sound but they assured me it’s safe and told me to replace the rotors when I change the brake pads. They spent at least 20 minutes on the car. Again, they did not charge me for this. They did not take off the wheels to do a proper brake inspection. Also, during this visit, I brought them an estimate from another mechanic where they told me the change the rotors/pads/axels everything. I was willing to have everything replaced with them that day but they told me none of the suggestion by other mechanic were necessary. They told me it’s too much. The only thing they agreed with them was the rotors.

I will come back this Saturday and I will ask them to do a proper brake inspection to make sure everything is right. I will update.