Checking my last day of health coverage - any advice?

I am not sure what date my benefits stop after being let go as an IT help-desk technician. I do not usually post, so bear with me. The letter is unclear about dental and vision. How did you confirm your end date?

I moved my appointments earlier while coverage was active. It saved me a bill.

Ask HR to confirm the exact date in writing. I also called the insurance company to double-check.