Account Seemingly Disappeared

This might be a bit lengthy, so please bear with me. 

I had a comcast.net email address that I set up about 14-15 years ago. I only used that email address up until I made a secondary email account through Gmail. Eventually, I moved away and set up my own internet service through Xfinity using my phone number and my Gmail account as the primary email address. 

The current predicament I am in is that to gain access to my old Comcast account, I am prompted to change my password. When I go to change my password, it says that I need to connect to my home WiFi to do so. I no longer have Xfinity as my internet provider, so I do not have a “home WiFi” network to connect to, effectively locking me out of that account. 

I have contacted Xfinity support multiple times and informed them of the situation on numerous occasions. When I give them the original email address that I was attempting to access (I could only provide the email address, as a phone number was not needed to link to the account when I made it) I was informed that nothing showed up in their system whatsoever in regards to an account connected to that email. I attempted to give a phone number too, but as I had guessed, that number showed up linked to my Gmail account and had no connection to the comcast.net account that I was trying to access in the first place. 

I’ve been wrestling with this for a couple of years now and truly have no idea what can be done. I’ve spoken to multiple members from Xfinity support, I’ve done everything I can to get back into my Comcast account, but I’ve truly hit a brick wall here.