The "ATT Make it Right" is not a scam. The text message was sent by ATT due to a network outage on Thursday. The cause of Thursday’s outage was due to an application and execution incorrect process, not a cyber attack.
The ATT Make it Right Text

Making it right
Keeping you connected matters.
We apologize for Thursday’s network outage. We recognize the frustration this outage has caused and know we let many of our customers down. We understand this may have impacted their ability to connect with family, friends, and others. Small business owners may have been impacted, potentially disrupting an essential way they connect with customers.
To help make it right, we’re reaching out to potentially impacted customers and we’re proactively applying a credit* to their accounts. We want to reassure our customers of our commitment to reliably connect them – anytime and anywhere. We're crediting them for the average cost of a full day of service.
We’re also taking steps to prevent this from happening again in the future. Our priority is to continuously improve and be sure our customers stay connected.
For more information, please go to the following link:
https://www.att.com/makeitrights/