Technical and billing

I’ve had Xfinity WiFi for a year now and every month I have to call customer service where I am transferred back and forth with someone who doesn’t listen to what is going on. There have been issues on the app where when I ask for a payment arrangement it lets me pick a date. I set it and it doesn’t save or go through. Leaving me with no payment arrangement. My services get disconnected, I get credited and the same thing happens every month. I am told I can’t make a payment arrangement over the phone I have to do it on the app. I was told 2 weeks ago after my services were disconnected for this very reason that my account would be credited and set as current with no balance remaining. Today I was disconnected and called and was told I need to make a payment of almost 300 dollars. So it’s obvious someone didn’t credit the account. I spoke with the loyalty department and they told me I would be transferred to billing because they need to manually credit the account so that it current. This is still unresolved. I spoke with the supervisor and she didn’t listen ofcourse and just kept breaking down payments. Not understanding that I should be current. Someone please help. The supervisor name was Roberta. Very rude.