Aside from "Don't fly Spirit?" If OLCI still isn't working, call them back and keep the agent on the phone until you're able to process your check-in. If they're unable to correct your record, have them put a notation on your reservation that you tried to check in online but couldn't due to the website issues so that you can get the online bag-check price at the airport. While you've got the agent on the line, you could always POLITELY ask for the bag fee to be waived entirely for your troubles. Good luck!