NHTSA Complaint #11474277 — 2017 MAZDA CX-9

I purchased this vehicle with 19K miles on July 31, 2020. I noticed on April 12, 2022, that there was a knocking noise coming from the left front suspension after leaving a Mazda dealership for an oil change. I called Mazda service and was told they only did an oil change. I have put 4 brand new tires and have replaced the front/back brakes, rotors and still hear noise going over uneven pavement. I brought it to my own mechanic twice and he hears the noise but informed me that he cannot order any suspension parts at all for Mazda CX9. He said Mazda are forcing Mazda customers to go to a Mazda dealership. He called 5 different places to purchase strut. suspension and was told they had none. He also said Mazda has a special wrench to work with having to do with suspension and he cannot get one. My mechanic had my vehicle for 3 days and said it's definitely a suspension issue. My Mazda only has 35K miles. In 2 years, I have only driven 16K (8K) per year. There is no way a suspension should go after only 35K miles. I am not off roading or abusing the vehicle. Can't NHSTA assist with this issue? This is very serious. I am afraid to drive this Mazda now.