Talked to apple support about this problem about not being able to purchase, I was able to add 10$ to the App Store, made a purchase and the apple tech support indicated that the purchase went through on their end... Kind of time sensitive since I have YouTube subscribers waiting for a new video.
The restore purchase or loading the purchases is weird in the app and should be fixed. Adding alternative payments or shifting the application to a web download app so people could use external payments easier would be really nice...
I understand your concern.
What is the email used for your account in the SeeMusic app? I can't find an account for either of the emails I've seen in your communications.
The only part of purchasing that occasionally has an issue on Mac is the recurring Monthly subscription. Since you're having an issue, I would ask that you please:
Cancel the recurring Monthly subscription now.
I will update your account and add an extra free month for the trouble.
When the subscription expires, please use the non-recurring subscription options instead - the 1 Year subscription is the best value.
I am currently a 1 man team, and in-app purchases are notoriously difficult to make bug proof across all platforms. I will explore other options when there is more time, money, and resources in the future.
Thank you for understanding.