Scammed!

I purchased a Netgear nighthawk model 84. last week. I scanned a QR code and go connected to a tech support firm called N-solutions. I went through their setup and was charged a user fee. I was able to get my router set up and WiFi working on all my devices. Later after doing some checking about N-Solutions (which I should have done first!) I read they are a scam outfit! I am concerned if they are able to connect to my system when my router is connected to my modem. I am presently direct wired to my modem, not via WiFi. I have changed some passwords already. Hope you can help for my security.