That issue was due to another plugin. You have not given me any information on the issue you are experiencing, you have not provided any config setup to reproduce your issue as well. I don't even know what the problem is that you are trying to post about.
Feel free to provide feedback with an additional post or add me on discord Khan#8615 to discuss this further. Preferably in as much detail as possible relating to your exact issues.
All I have to go on is that you have issues with sales relating to custom currency. You don't provide a config setup or specify what custom currency you have it set to, you don't provide the plugin version number, an error, or what is happening other than you simply say hey my custom currency isn't allowing people to sell things. You don't say if it's all the shops affected or simply custom shops. You don't say if it's NPC shops, etc.