Support
Support comes from the people who wrote the extension
There are two ways to reach us, and they arrive in the same place. Treat any other address or site you find as not ours.
The shorter path if you already know what you want to ask. A developer reads it.
Support portal
Worth starting with if you would rather search first: it holds the answers we have already written up, and it gives you a ticket you can follow.
A request that says which extension and version, which OpenCart and PHP version, and what you expected instead of what happened can usually be answered on the first reply. The documentation lists what to include, and what never to send.