When you first create your SplitFit account you'll have provided your credit card information (we need this information on file even for free sessions). From time to time you may need to update your credit card information (use a different credit card, card has expired, etc.
Go into settings (top left screen):
Tap on 'Payment Method':
Update your information accordingly. NOTE: this will only apply to new transactions going forward.
Please contact SplitFit Support with any questions (firstname.lastname@example.org).