iceGear is a one-man small company based in Japan that develops audio plug-ins (effects and synthesizers).
For apps that are compatible with both iOS and macOS, if you have already purchased the app on your iOS device, you should be able to download it for free as long as you use the same Apple ID on macOS as on your iOS device.
Unfortunately, the Mac App Store is known to have a display bug regarding apps already purchased on an iOS device. In this case, you should still be able to continue the purchase process and eventually download the app for free.
This issue can occur with any app for both iOS and macOS. The same problem can occur in any developer's app. This is an App Store issue and as a developer I am not competent to resolve issues that occur within the App Store.
If you are not satisfied with your Appstore purchase, please contact Apple Support as soon as possible for a refund.
▶ Request a refund for apps or content that you bought from Apple (https://support.apple.com/HT204084)
For any issues or questions about the App Store, please contact Apple.
Should you have any questions or need more information, please do not hesitate to contact me. I do my best to check and reply to e-mails on weekday evenings, Japan time. If you have not received a response from me after a few business days, I suggest you check your junk mail folder. Also, depending on your e-mail provider, my e-mail may be deleted. If you do not receive a reply from me, please resend from a different e-mail address.
I only provide customer support via e-mail. I do not provide support by phone, social media or any other means.
Your suggestions and bug reports are highly appreciated and have been of great help to me. However, as a solo developer, I am unable to provide compensation for any contributions you may make. While I will do my best to take your feedback into consideration and make improvements where possible, please note that I am not able to offer monetary rewards for your ideas or bug reports. Also, please do not share with me any ideas or information that might raise intellectual property issues.
If you need my assistance in resolving your issue, please e-mail me with the following information. It is difficult to provide support through App Store reviews.
I appreciate it if you send me your requests about my products by e-mail. However, please note the following when submitting your request.