New Fiber installation with /27 addresses - block was previously blacklisted

We just switched to ATT fiber and received an ip block of /27 addresses. The block was previously part of a /19 block that had been blacklisted by numerous organizations (Spamhaus, sorbs, trendmicro, barracuda, etc) and running into difficulty to get exceptions in their lists. Several have requested that the NOC from ATT request an exception on the block of ipaddresses. ATT tech support tier 1/2 and supervisor does not understand the issue and thinks its an issue with the modem (which is not). Does anyone have a 'hidden email' for tech support at ATT in network operations that can assist in clearing the blacklists? Alternative suggested by ATT is to get a new block of IP's - something that would put us down for 48-72 hours as DNS addresses propagate -- any there is ZERO assurance that the new ip addresses would be any better.