Same SIM card, new phone has wreaked havoc in my home network

EPIC SUDDEN ISSUES

(but not the first issues,ever)

I have had the same ATT internet for 12 years, now.

ive had it at my current address for 5

ive connected to it using my same phone for 4 years.

i hate computers and tv so i mostly use internet on my phone, at home 

recently, my 4yo phone got cracked terribly(pieces of metal breaking off) so i bought myself the same brand with in a newer "play(er?)" model because it was a cheaper option.

I was using my internet in my home  with my phone on saturday when i transferred my long term phone's SIM card to my newer phone model of the same phone brand/type.

att would not recognize my sign in to the network.

i tried again.

i cleared my phone cache

i rebooted my modem

i rebooted my phone.

i did it all three times

i did it all three times again,on my laptop ( i only use it for work projects) 

i was asked to do account verification between emails on both devices 

i did it all again waiting longer in between each step

 i phoned  customer service

i went through the automated menu options

i was told the office was closed as the final Ai menu redirect

i donwloaded attsmarthome (ill refer to it as ATTSH)

ATTSH tried fixing my problem

 ATTSH said it had been fixed

I connected but it said couldnt bring me to the webpage i would try to open

On one attempt, i tried checking the problem was fixed by  going to youtube and was given a warning that the connection was not private and to "return to safety"

i tried again wirh ATTSH at least three more times

i checked again that all my cables are not freyed, etcetera

i tried plugging the boradband chord into the ethernet ports, thinking maybe id misremembered how to hook it up.

Then, my broadband light atarted blinking red and hasnt stopped.

ATTSH informed me that a tech would be scheduled to come

i dont have the sanity or energy to write what happened with three differnet ATT agents since last Saturday.

my network shows up as an available network  but "no internet" 

i will edit what few photos and screen shots i had the presence of mind to record.

ill edit out/hide the private info.

Ill upload here, as a "response" to this post when i have the time/energy/will to live.

thanks for reading