Checking my last day of health coverage

I was told my coverage ends on my last day, but the letter says the end of the month. I do not usually post, so bear with me. I do not want to be surprised by a bill. 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.