MobilityWare doesn't handle the transactions for purchases in the game. All transactions and payment methods are managed by Apple iTunes or Google Play.
If you need to change or edit your payment details, please follow the applicable link below:
Apple iOS Support: https://support.apple.com/en-us/HT201266
Google Android Support: https://support.google.com/googleplay/answer/4646404?co=GENIE.Platform%3DAndroid&hl=en