connecting to internet

when my grandson was pausing devices on my Cox panoramic wifi and saw a device that wasn’t recognized except by the letter c and then some numbers and letters. He thought someone had hopped onto my internet and paused that device. After that my iPad doesn’t show up among the list of items on my WiFi and my internet will not let me log onto it. (All tvs and such are connected and show up) Could he somehow paused the internet ipad connection to my internet specifically. The iPad does log onto my friend’s internet just not mine. Would it be an iPad issue or just my Cox gateway somehow was messed up in some way?