ATT Contact for DDoS?

Trying to figure out whom to escalate to with ATT to help with a DDoS attack for a network, we are trying to help out. RTBH is not sufficient because they are hitting a large swath of IPs out of the prefixes advertised, and the targets are moving. The network AS itself is the attack target. I'd heard of other operators working with their transit provider's Cybersecurity NOC to filter traffic outside of the US. Does anyone have a good ATT contact for this? Sajan Parikh sajan@parikh.io 262.343.5973