I now have a collection due to service address change errors.

I moved into my first apartment alone from my childhood home at the end of Dec 2024. I had put the Internet in my name after my father had passed for my family to have service. When I was inquiring about the upcoming move, I was told I'd have to pay $357 to be eligible to do so. I paid that, and provided all the necessary address information for the change to be submitted. Once I was moved in and called about setting it up, they had asked if I want new equipment or if I was bringing it over. I said I brought it over and they said that is all good, just let them know if it doesn't work. It worked fine, and for maybe 2 months my very same xfinity account I had used for all of this process said I was in good standing. I wasn't sure if it was the $357 I paid to be able to move it being probated or if the billing cycle just had to start on a fully fresh cycle. I then had my Internet suddenly shut off, so I called to find out what is going on, and I was told that I owed $800+ and it was disconnected. I had just moved on my own with no support and had no way of ever paying that, and couldn't even comprehend how I owed so much..much less why my account was showing me I was fine. I tried to call over and over again to explain what happened and explain that it doesn't make sense. I even at one point gave up and since this was my only internet access in a basement apartment, and I was not being given any understanding or resolution for a mistake that had nothing to do with me or any intention to withhold payments. I even asked if I could at least do a payment plan, and was denied that essentially guaranteeing the collection I now have and not knowing what to do if xfinity is the only provider wherever I might be in the future. $944 is an absurd amount to have owed, not only so quickly, but with genuinely no warning or understand how. I already had my credit affected by this and it is sold off to a third party, so I would greatly appreciate any help from somebody with actual understanding and access to what is needed to solve this. 

thank you kindly,

-Ryan B.