Yes. For our half of it.
We support delivery, installation and updates. A download that will not install. A plugin that is not activating. Updates that are not showing up in your WordPress dashboard. Open a ticket. That is our job, and if something is not working the way it should, fixing it is our problem, not yours.
What we do not do is teach you the plugin. How to build the form, why your layout broke, what a particular setting does. That is the developer’s own support, and it is one of the things you give up by not buying direct. We would rather say so up front than let you find out on a Friday afternoon.
For that kind of question, the developer’s documentation is usually solid, and the WordPress community forums are genuinely helpful. And if there is one plugin you live in every day, buying that one direct from the author is a sensible move. Plenty of our members do exactly that, and use us for the other forty they need once in a while.
Anything to do with getting your plugins installed, running, and updated: that is ours. Open a ticket.