zlacker

As a network engineer for an ISP, I can tell you that StopForumSpam reports generally don't make it on our radar. Cisco Talos IP reputation, SpamHaus, SpamCop and various other DNSBLs do make it on our radar and are proactively monitored by most responsible ISPs.

That being said, the proper way to report abuse to an ISP is to email the official point of contact for abuse associated with their IP netblock. In the case of Zoho, that contact info can be found here: https://bgp.he.net/AS2639#_whois

ARIN rules require that all IP netblock owners provide a valid point of contact for abuse issues. ARIN validates the points of contact annually. I believe that RIPE, APNIC and LACNIC have similar rules.

If an ISP doesn't act on the abuse after it has been reported to their abuse point of contact, then you have a legitimate complaint against them.