Wi-Fi hit or miss on connecting, when connects all my websites have potential security risk warnings , what do I do?

Our Xfinity cable and internet went down earlier today for a few hours. We were supposed to have a tech come out fix everything, but it wasn't going to be for 3 days. So my dad tried calling back just and got someone who said they would try to walk him through everything, but he's not able to understand computer stuff so I went on the phone and spoke to the person. The cable TV started working again, and our Xfinity modem finally went back to the solid white light, and the person on the phone kept telling me that our internet was working, but I kept telling them it was not. They changed the name of our modem and the password. I'd reset the wi-fi, I select our modem, I'd enter the password, and everything would seem to work for about 10 seconds, then I get a message asking me if I wanted to be able to switch between wi-Fi or stay on them, i said switch cuz that's what I always do, and then it suddenly would open a browser page telling me I had to go and fix my settings on the xfinity app i kept telling the person on the phone this. I would then try to just open a different link or a different app away from that, but then I was getting the security messages. I was trying to explain this to the person I was speaking to, but they didn't seem to understand what I was saying. They just kept telling me to remove my modems name from my Wi-Fi list , reset the list, and just keep trying again over and over and over. But it wouldn't work. And then they finally just said well it says your internet works so we can't help you you have to wait for the tech. That's 3 days away. I have been racking my brains for the last 3 hours trying to figure out what [Edited: "Language"] is going on. Sometimes the internet seems to work, but then other times it just will go from whatever website I'm on to the message saying that there's a potential security risk. I've never had this message before ever. It's really bizarre. Also I have the Xfinity app on my phone. I don't know what it's telling me to do with the app because I have the app set how I've always had the app set. I live with family and they use the cable TVs on the first floor of the house, but I live on the second floor and don't have access to a tv. So all I have access to is my Wi-Fi on my laptop. I do have my cell phone, and I have access to mobile data, but my phone is very old and very broken and overheats extremely quickly so I'm pretty much stuck with nothing . I'm medically disabled and I'm literally stuck at home all the time so right now I'm just staring at a wall basically. I'm not super tech savvy, but I can manage to walk myself through stuff if somebody has an idea of what I can do here. I just have absolutely no clue. Again this is never been a problem we've had before. My parents are getting the same type of warnings on their phones and their computers just like me. I just don't know what I'm supposed to do here. And again waiting 3 days for a tech is going to be very very [Edited: "Language"]. I know it's a first world problem , but I can't read books because of my site, I usually just watch and or listen to movies and TV shows to get myself through my day and to try to distract myself from my chronic severe pain. So the idea of having to go through the next few days with absolutely nothing to do is pretty daunting. Again first we'll problems and 100% aware of that. I'm just hoping there's something that I can do to fix this because I honestly do not understand what [Edited: "Language"] happened to cause this to happen. Sorry for rambling I'm just trying to explain what's going on a bit and my situation and why I'm so desperate for something to do to fix this.

I have no idea if there's ways for me to add screenshots so that I can show what pops up. I either get a page that says "warning: potential security risk ahead" , or I get a link to the xfinity Gateway>login, which no matter what I answer into username and password it will not allow me to log in through a browser.

Any suggestions, ideas, links anything would be extremely appreciated. Again , I'm not super techy but I'm able to manage most basic kind of things. If it's a little bit more complicated and there's a walk-through instruction, I can do it.

TIA