Did you book the cruise directly with Regent (Radisson's new name) or with a travel agent? If you used an agent then you should contact the agent and the agent inquire about the documents and the status of the booking.
If you have a valid booking number and the cruise line has charged your credit card for the final payment you should be fine. The agency should not have charged the payment.
I have received documents anywhere from 60 days to 3 days before boarding. Actually, you don't need documents to board the ship. If you are on the manifest and have proper identification you are good to go.
Have a great time. I'm quite sure you will have a wonderful time on your Regent Seven Seas cruise.