I see that you've been getting a message that your payment method needs to be verified whenever you try to download an application from the App Store. I'm happy to help.
Payment methods that you can use with your Apple ID -- Review the information in this article to be sure you're using a payment method that's supported.
Change or remove your Apple ID payment information -- If the payment method you're using is supported, try updating the payment information from a different device. This article explains how.
If your payment method is declined, or you have a billing issue with a previous purchase in the iTunes Store -- If there was a billing issue with a previous payment method, review the information in this article.
Let me know how that goes.