4G S8 to be disconnected with 3G shutdown - here is what you can do
If you own a Samsung S8 starting with model number G955U or G950U, and you have received a text/letter from AT&T saying they will disconnect you in February for using a 3G phone, take note.
FIRST: Your phone is 4G and should is supported. Samsung has confirmed this for me and showed me an AT&T web page that doubly confirms it (see https://www.att.com/device-support/article/wireless/KM1273778/Samsung/SamsungG955U/).
SECOND: AT&T is ignoring complaints about unilaterally disconnecting 4G phones under the guise of dropping 3G service. Some are speculating that AT&T is railroading you into upgrading your phone when it is not necessary.
THIRD: You should make your concerns heard by the following interested parties:
SAMSUNG: They should be concerned that AT&T is misinforming customers about Samsung product capabilities. Here is a shortcut to voicing your concern https://www.samsung.com/us/support/contact/?model=N0022597&topic=SYM0000442
FTC: Since AT&T is providing customers fraudulent information, telling the Federal Trade Commission about it will get a response. Visit https://reportfraud.ftc.gov/#/form/main?pid=B
FCC: Since AT&T rents the public airwaves, and since the FCC has many consumer protection rules, they too should be made aware at https://consumercomplaints.fcc.gov/hc/en-us/requests/new?ticket_form_id=39744
Be sure to note that (a) you have a 4G phone, (b) AT&T is incorrectly identifying it as 3G and (c) is preparing to kill your service in February (and maybe scaring you into upgrading).