Extra routers on (Private Network)

For the past few months I’ve been getting constant routers on my network. I have done fresh installs of windows using the Microsoft Creator edition to verify it wasn’t me and synced straight to my router. These devices are not mine and seem to be neighbors who have been on my modem or is part of my network with their router. I have bypassed the router to verify this and tried it on both my computer and my wife’s computer.

The names of the devices are as follows with mac addresses attached to them. I have been blocking/rejecting them through my router firewall and I have been using McAfee's firewall to deny connections or sharing. The serial numbers on the routers come back as 12345678 or 8888888.

 My current setup is CM600 and R7800 both Netgear products. I have already updated my R7800 to the latest version but my CM600 is lacking in the update and is stuck on Firmware Version V1.01.06 and I need the firmware V1.01.12 to get loaded onto it because of my lousy neighbors.