Unreliable. Breaks unexpectedly but when it works, it works well. You see if you're going to make a plugin that people rely on to accept donations and payments, it should never just break and break other plugins.
In Wordpress, plugins are not isolated, and a broken plugin or theme can prevent other plugins from working properly.
Fortunately, these conflicts can be detected in most cases, and resolved in a way or another.
It's pity you haven't contacted our support to help you sort out this issue.
You've given us a one-star rating, but we haven't got the chance to help.