If you get an email from AT&T saying they’ll stop supporting your phone in 2022, it isn’t a scam letter. Some phones will no longer work on the AT&T network sometime in 2022. If you have a 4G phone you should be good, but the 3G AT&T network is going away in 2022. This link has the story- https://www.theverge.com/2020/7/22/21334221/att-customer-upgrade-email-3g-shutdown-2022