Issues since new Xfinity Gateway arrived

I have been on the phone with Xfinity reps for approximately 8 hours last night and today.  This has been unbelievably frustrating.  I received a "new" XB3 gateway on Monday.  I have no idea why I was sent a new gateway because I was not having any issues at all.  According to the letter that was in the box, there was an issue with my gateway.  If there was, I could not tell.  I plugged in the new box and ran a setup.  Everything seemed to be working fine because I had access to the internet and could stream Netflix on my Xbox.  Last night (8/3) I tried to play one of my online multiplayer games and was never able to connect to the ingame severs.  I checked my settings and setup port forwarding and verified that UPnP was enabled, it was.  Rebooted the gateway and my xbox with no luck.  I called xfinity and the rep was unable to help so she elevated my call.  The second person redid the same things I had done with the port forwarding, but it did not help.  She thought she had fixed the issue, even though I told her she had not.  It was late so I figured I would try again in the morning.  This morning I called and spoke to another rep that was confused why I ordered the same gateway I already had.  Again, I did not order a new gateway.  She attempted to reset the gateway and a few other things to no avail.  While I was on with the rep, I logged into 10.0.0.1 to look at the admin settings.  To my surprise, I was not logging into my gateway.  I was logging into my neighbors.  I tried to explain to the rep, but she did not understand.  I could be wrong, but the name of the gateway was the same as my neighbors Wifi connections.  She could never understand that I was logged into what I perceived as my neighbors gateway.  Before we ended the call, she said I needed to replace my XB3 gateway with an XB6.  I told her to send me one.  I have started experiencing issued with the VPN I have to use with my work laptop.  It almost constantly connects and then drops the connection.  I am assuming this issue could be multiple items.   I just want someone to help.  I have called Xfinity at least 5 or 6 times in the last 24 hours and cannot get anyone to fix an issue that started when I setup the gateway they sent.