Keep being charged for months for a not existing account

In September (9/4) I call to cancel my Internet account because my bill went up 2 months after I sign up for a fixed lower rate.

I'm convinced to stay. I'm assured that it was a mistake, I'm given back an Internet rate close to the previous one and offered a free phone line and android phone:

order #xxx[Edited: "Personal Information"], tracking number: xxx[Edited: "Personal Information"]

On the same day there is also a second order: #xxx[Edited: "Personal Information"], tracking number: xxx[Edited: "Personal Information"]

When I notice that, I call Xfinity and I'm told they would cancel the second one.

FedEx said that on 9/9 the shipper recalled shipping xxx[Edited: "Personal Information"] (Delivery exception Damaged, handling per shipper instructions - on the FedEx page)

I'm trying to receive the phone but I'm unable because I don't work from home and FedEx can deliver only during the day with a large window and does not allow me to pickup the phone (per shipper instructions they say - even if the Xfinity email says that I can pick it up at FedEx)

I'm trying to retrieve the phone but neither Xfinity or FedEx can help

On 9/15 my account is changed again and my internet increased to $109/mo.

When I find out, I call Comcast/Xfinity and ask to cancel all my accounts

- I was unable to receive the phone and activate my mobile line

- too many surprising increases in my internet bill

Order #xxx[Edited: "Personal Information"], tracking xxx[Edited: "Personal Information"], had been returned to Xfinity as undeliverable.

I returned the modem and streaming devices in my possession.

They say order #xxx[Edited: "Personal Information"], tracking xxx[Edited: "Personal Information"], had been recalled by them and would not be a problem.

They assured I would receive a refund and no further charges.

But I did not receive the refund for order #xxx[Edited: "Personal Information"] and in October I'm charged again. 

I call, explain everything and I'm assured that my accounts are closed, I'd receive a refund within a couple of weeks and no further charges.

But in November I'm charged again. 

I call and I receive the same assurances.

And in December I'm charged again. 

This time I receive a call. I think it is a follow-up from November, instead I'm told that I'm in default because I should raise a complaint about a shipping problem. It is the first time I hear that, I'm not receiving clear instructions on how to do that.
Since the phone calls have been misleading and ineffective, I'm writing here.
I did not find any way to submit a ticket. The emails I receive say not to respond, the address is not monitored. The chat bot cannot answer and does not allow me to talk to an agent since my "Xfinity account is no longer active."
Even if my account is not active and I never received any service from Xfinity mobile, I keep being charged and am not given any effective communication means where I could receive a follow-up. I hope someone will reply to this post and suggest how I can resolve this problem.