I have this same problem and I am at my wit's end. I can't book anything through the app, and neither can my cabin mate. I did try creating an account with a new email and that didn't help at all. Support has been useless. I don't want to spend my days at the sailor services desk every time I want to book dinner or shows.
My booking was for San Juan too and dates were switched. I was paid in full and when they transferred my booking I had a payment due for -$1. SMDH