It looks like it's not possible to have the "add to todoist" button if you're using the navigation pane mode. is that correct?
Yes, Preview Pane (navigation pane) blocks our extension and prevents it from working. We hope we can find a workaround but as of now, that is correct.
I need the navigation pane and without the "add to todoist" button, this product is not useful for me because I can just use google tasks. How do I get a refund?
Sorry to hear that. Please let me know your transaction ID or reference number from the purchase and I can do that for you.