Connect App - Not connected to Home Network

Hi

After 2 years I finally got Fiber Optik 500/500. They put 2 wifi6 plus hot spots and one booster. They won't show up in my app. I had them change the SSID and password on the backend so my devices would connect. They said they should automatically show up after a few days, but of course nothing. Then when I phoned again, they said there is something wrong with the app and I will have to wait? Is there any way to manually add them? Or connect to them to change the SSID and password without the app? 2nd question. When they came to install I asked if I could just use my old Telus Wifi extenders but the tech said he was going to just install the new boosters. Not realizing that I would be charged 10.00/month for wifi plus. I told them if it was not a requirement I would like it cancelled and removed, but if they did that would I lose wifi. They said they would cancel but I wouldn't lose wifi. So I see people are selling these wifi6 boosters on Facebook. Can I just purchase and add them and be done in order to get wifi6 plus?