I am never again using the Suburban Express service for my Champaign-Chicago trips. After dealing with their awful customer service and having heard many similar stories, I can firmly say this is the worst company I have ever dealt with, period. After over a dozen attempts to call them during their listed telephone hours (for over a week!) and several trips to their office, and no answer, store closed, every time, I gave up on getting my issue resolved. I lost $30, but at least I know now never to go back.
If you do end up using Suburban Express, do so at your own risk. I have even heard stories of customers being 'banned for life' even when the bus was to blame.