Xfinity app is horrible

I have been having the same issue as others as of late and I was hoping someone could guide me in the right direction. I was attempted to switch to a new modem and router and of course, my internet starts messing up after I installed them. I decided to switch back and thats when all [EDIT: Language] broke loose. The online support person did something to my account and the app is now totally useless to me. The only solution they are giving me now is to have a tech come out and look at my devices. Had 2 techs come already and check on a signal failure. turns out the cable box wasnt broadcasting at the signal they believe to be the correct range. That did nothing for me. How is that related to the app not working properly? This is the [EDIT: Language] Im dealign with.