Checking my last day of health coverage, school bus driver here

I was told my coverage ends on my last day, but the letter says the end of the month. I have read a lot of threads here and could not find my exact situation. The letter is unclear about dental and vision. Did coverage match what HR said?

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

Keep everything in writing and save the confirmation numbers. It saved me later.