Toyota Corolla Chassis Corrosion Despite 12-Year Warranty, No Support Received

I discovered severe corrosion on the underbody chassis profiles of my Toyota Corolla, which supposedly comes with a 12-year chassis warranty. Shockingly, this issue appeared in the 11th year of ownership when I lifted the vehicle for inspection. I contacted customer service, and they directed me to the service center. A representative at the service inspected the vehicle, took photos, and assured me that I would receive a response within a week. However, I have yet to hear back from anyone. Additionally, the service representative mentioned that this problem is not covered by the chassis warranty, which is deeply concerning. I am disappointed that a reputable brand like Toyota is not standing behind its vehicle. I request that senior management take immediate action to address and resolve this matter.