My card is not working on appstore

Did you already try the troubleshooting mentioned in this related article?

If your payment method is declined in the App Store or iTunes Store

If so, and that did not solve your problem, use this link as a start, to contact the official Apple Support about that, only they can look into your personal settings to find the reason for that:

Contact Apple Support

Sorry, I forgot mention, that by clicking on the blue links, new articles will open, providing you with all the needed details.