If it was me, I would be concerned. If the hacker is doing something real bad, the FBI will show up on your doorstep. They would have to be somewhat close to get your WIFI signal.
I do not know what router you have, but there are steps that you may be able to take that may help.
Change your router userid and password.
Turn off the router/Modem when not in use.
Keep checking and pausing when you notice them.
You may try moving your router or lowering the transmit power (WIFI router option) so you get the signal but the hacker does not.
Change SSIDs and passwords and use a very long hard password.
If your router has the options, a few things to try:
Make sure you are using all of the security features for WIFI.
Use WPA/WPA2 as that is the strongest.
Be sure remote management is turned off.
Set local management to be only selected PCs.
Set up wireless MAC filtering where you must enter all of the MAC addresses for all of your devices and allow only them to access the WIFI.
Set up Parental controls.
... View more