I have received about 5 of those emails since nov 1st all saying the exact same info as yours. I am 99.9% sure they are a scam because the info given is not correct. The password they are claiming is mine, is not... it's a very old one. And the router info I was given is actually the same as yours. Do not do anything.
Got similar mail at work. Went to IT and they said happens all the time and don't worry just change password anyway. My email came with a Subject: YOUR PASSWORD IS xxxxxxx. It was a password from 10 years ago but I had used it at one time.