If you really factory reset your router you should be able to find Wi-Fi network of router. Should be on one label on router, Wi-Fi name and also password. Re-connect and put correct settings that isp will provide. Or Call ISP, describe problem, ask for support. Maybe they can re-configure the router remotely ( I doubt this). Ask isp for what you need to configure. Or ask a friend with Ethernet port to help
There is a possibility that they can see MAC address of device, name of device, etc If they provided Wi-Fi Acces for personal devices you should be ok. Hope is not a porn site, the It guys will be able what site you tried to access. In the future try to use only legit apps and websites while on job.