Dealing with this now. Apparently a wide spread issue for people canceling towards the end of the year also. I have a balance that they never sent a bill to me for. I paid my final bill in 10/2024 and DTV even says final bill. They then decided to bill me because their system glitched. It's now in DTV collections, some internal group, so retention can't help just crediting it. So after 7 months, they say I owe them but terms say billing has to be resolved within 60 days, even the equipment return. They also haven't even sent a paper bill.
Edit - Supposedly they sent an email bill to me. I told them that would be a phishing attempt to me since I no longer have an account and they need to send paper bills to everyone. I was able to finally get to a supervisor in retention that was able to reverse the actual contract since it was for a receiver swap out and nothing new. If you end up talking to a person in the DTV Collections group, prepare to bang your head against the wall.