I know that collection accounts stay on your credit report for 7 years, but my question is once that 7 years is up is it totally gone even though it was left unpaid?

I can't say for sure, but probably not if it's not paid and by then, that collection agency may have sold your account to another collection agency so you might have two accounts stay on your report. Pay it off if you can.

Yes, it should be completely removed off your credit report.