AT&T Phone Account

I am trying to help my mother transfer her landline phone number (that she's had for over 50 years) to her new cell phone. The new carrier has asked for a port code which I cannot seem to acquire. What I've tried: 1) We are not able to use her landline to make or receive calls. The account is

Bonjour un amis ma offert Google pixel 6 pro je n'arrive pas à l'utiliser le téléphone n'ai pas débloqué pouvez vous m'aider ?

My home phone is not working. I have internet but I get the busy signal when I try to use my phone. Normally I have three signal strength bars on my at&t model IFWA-40 device but now I have none. I had the sim card replaced but still no signal. Where do I go next?

How on earth do I cancel this service (and TV too?) I can find just about everything else, but canceling seems to be hidden in order to make it difficult to cancel? If the service were competitive and good they wouldn't have to use deceptive and unethical means to keep you paying.