Unfortunately, there is an existing bug affecting a small subset of people, where it can have trouble loading your settings (which are stored on S3) which can cause issues in usage of the app.
I am working on a fix, and hope to have it submitted shortly, but unfortunately that might take as long as a week for it to go live on the app store.
I wish I could issue a refund while this is all sorted out, but afaik, that isn't available yet via the app store. I'll let you know however immediately, when the fix is available.
Gabriel