Icarus Verilog is the Iverilog Wikia.com wiki, and that is the first place to start for help. (There is also a legacy FAQ here.) If the documentation and the FAQ fail you, then try asking your question on the mailing lists. I and other contributors read the list regularly, and I encourage users to subscribe to the list, so in that forum you have a chance of getting a human being to help you.
If you think you have found a bug, then see the "Bugs" page. This tells you how and where to report bugs with the software. I try to promptly look to bug reports, but this is free software that I work on when (if!) I have time so please don't get impatient.Support Providers" page contains a list of individuals and organizations that have expressed interest in providing Icarus Verilog specific commercial support.