how to behave with harassing extension buyers

A week ago a person bought an extension of mine, then he requested support via the ticket system. I asked him ftp access and opencart admin access to fix a few code lines, but he denied me both accesses.
Since then he seems to be paranoic thinking i want to harm his website installing spam software on his website, sending me continuosly negative emails, writing negative comments on the extension page, both are very annoying. One of them was pinned to "what users say about...".

My questions:
1) How to behave with such users?
2) Is it possibile to report and ban such users?
3) Is it possible to remove the comment from "what users say about..."?

Thanks in advance for any advice
Viviana

You cannot remove extension reviews, but you should report the user to the OpenCart team for harassment:

https://www.opencart.com/index.php?rout ... rt/contact

Thanks for the advice, will try that way, because, as i said, it's getting very annoying. Hope i'll get a reply from Daniel.