When does my employer coverage actually end? (update)

I was told my coverage ends on my last day, but the letter says the end of the month. Any experience at all would help. I have an appointment next week. How did you confirm your end date?

Thanks for writing this out. I went through something close to it last year, and it settled down once I kept a simple log of every call and form.

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