Sorry but it's simply not possible to answer to everyone within 24 hours. Also buying paid plugin does not mean you buying something with "premium support".
FurnaceLevels plugin is small one time payment which after fees and taxes is brought down to 3-4$ for developer, for this amount of money I can guarantee that
I will keep file updated to best of my abilities but you can't expect me to jump on every issue within 24 hours, it's not monthly paid service.
Anyway in future I do plan raise prices and hire someone to deal with customer support so I guess it wont be issue anymore.