Removing of known devices from a Cisco router

Dear all

I am in the situation that my neighbor accuses me of having used his internet connection by connecting to his Cisco router from my home via Wifi.
The router is a Cisco EPC3828D, i think this is an older one and I cannot find any documentation.

When analysing the routers user interface, the only devices listed as known by the router are devices owned by my neighbor and his family, but no device of mine.

As far as I know from other router brands, the only ways to remove a known device from the router list, is to do it from a device but not the one with which you log into the router as it is not possible to remove a device actually connected. And the other way would be a factory reset either using the user interface or a reset option an the devices hardware, but this would also erase the saved internet credentials to connect to your provider, so it should be reconfigured to connect to the internet (provider).

Could someone please confirm for the router EPC3828D that:
- It is not possible to delete your own device in use from the known devices list and that to remove a device from this list one has to use another device which would then still be listed.
- A factory reset would also remove the saved internet provider information / credentials and would be noticed by the owner.

Thank you very much for your help.