You can apply the credit balance towards your next purchase with C&J
If you have a C&J account:
Log into your account prior to purchasing your ticket. Once you select your travel date and time, it will bring you into the purchase process. On the top of the credit card page there will be section that shows your credit balance and you can apply the amount towards your purchase.
If you do not have a C&J Account:
Go to the email with your credit value. Click the copy code button and go to www.ridecj.com. Once you select your travel date and time, it will bring you into the purchase process. On the top of the credit card page there will be coupon code box section where you can paste the code and it will automatically apply the amount towards your purchase.
Note: Credits are valid for 365 days from the date they are issued.