In over 5 years of using Spigot, and purchasing many premium plugins, this has to be one of the worst developers I have ever had the displeasure of trying to get "support" with.
To be as brief as possible, the regex in the plugin was simply not working for me (
https://i.imgur.com/Cp5VpZ9.png). His initial "solution" was that (and I quote): "I really do not know, why this happened... But ChristmasMail won't be available." I (obviously) wasn't happy with this as the ChristmasMail was the reason I purchased this plugin to begin with after looking through Spigot's resources related to Christmas.
I expressed this to Sobky and the "fix" I received was a jar without the regex checking enabled. Sounded fine until the plugin couldn't see the player online (
https://i.imgur.com/2aW14xw.png). He didn't seem to look into why this was happening further, and advised me that it was "my java" causing the issue.
He became increasingly rude, with comments indicating that it is not _his_ fault his plugin is failing, and continued on about how it must be something with my system. The end of the conversation was Sobky stating that (and I quote): "it seems that your server does not support regex matching", which is an absolute pepega of a comment as I have _many_ plugins that utilise regex (and checking if players have ever been on the server) before with no issues.
Although the idea of the plugin is good, it's terribly coded (based on feedback from a developer I asked to decompile it - such as main thread SQL on constructors), Sobky offers very little "support" without able to accept there's something wrong in his code, and overall this has been a terrible experience.
I wouldn't recommend this plugin, or this developer to anyone.