When does my employer coverage actually end? after 4 years as a web developer

I was told my coverage ends on my last day, but the letter says the end of the month. This is my first time dealing with any of this. I do not want to be surprised by a bill.

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

Thanks for writing this out. I went through something close to it 13 months ago, and it settled down once I kept a simple log of every call and form.