Where do I go to to shut off certain app notifications?

I got a bill due reminder notification, through this app. Not through email or text.  That rubbed me the wrong way, and then to rub the salt in, when I went to open the app I got hit with "Looks like you need to update this app"....Mind you the bill due reminder notification push worked just fine on that very app. 

There is no way to shut off certain notifications on the app, my prediction is they will send xfinity product advertisements to worm around the email and text opt-outs.  No means no, xfinity!

Oh, about my bill, I am not behind, I pay once a month, they know when I pay as I never pay twice in one month.  

My next complaint, when I asked to change the bill due date, I think I only got that due date a couple of times, and then it started back sliding, originally due on the 3rd of the month, I asked for the 6th, I get either the 4th of 5th.