Help Installing OpenCart Multi vendor Marketplace Plugin by Knowband

Hello,

Does anyone installed successfully this plugin? The instructions they provide are badly written and vague:
https://www.knowband.com/blog/user-manu ... ce-plugin/

The issues I am having are:

The Problems are:

1- When I try to input the API key to enable the plugin I get a message that says "signature don't match"
2- The multivendor plugin doesn't show up in the modules or market place menu for installation.

FYI I have successfully installed the vqmod module so everything should work fine, I also followed the instructions and copied all directories for the multivendor module and changed all permisions as per the instructions, but it doesn't work.

Any suggestions how to fix any of the issues will be appreciated. Thanks.

You paid for it, ask them to help you.
Mike