Access old email address?

I used to have a comcast email address under a different address. Years have passed, accounts have been closed, reopened, I moved out of my parents house, etc. Now I do not know what happened to that email address, but I was wondering if there is any way to gain access to it again or change my current comcast email address to that one. When I try emailing the old one, I get the bounceback message below. Given this, the email address is not being used and should be available, and I would love to reregister it. Can a comcast representative help me with that?