Hey Sanjuanhillsinc,
We understand you're having an issue with in-app purchases specifically with WSOP app. We'd be happy to help.
Great job reaching out to the developer since the issue appears to be isolated to their app, however if they're not able to assist, you'll find more info on in-app purchases here: Buy additional app features with in-app purchases and subscriptions
If your payment method is being declined when making in-app purchases for this app, also review: If your payment method is declined in the App Store or iTunes Store
If all else fails, contact Apple Support using the following link for more help on the matter: Get Support
We hope this information helps out.
Take care!