Account Review

I can't download or purchase anything on my iPad at the moment.

If you can't make purchases or update apps, including free apps, you need to update your payment method or add a new one

See the following Apple articles:

Payment methods you can use with your Apple ID

Payment methods you can use with your Apple ID – Apple Support (UK) 

Add money to your Apple ID balance

Add money to your Apple Account balance – Apple Support (UK)

If you update your payment method or add funds to your Apple ID balance, It would take about 1 to 3 business days in order to process.

If you're still unable to update your payment method, Contact Apple Support.

Hello ~ Go ahead an contact support as this is Apple’s way to let you know that there may be an issue with your account.

If you see a message that says 'Your account has been disabled in the App Store and iTunes'

Contact through link or by going to upper right hand corner and click on Get Support or:

Contact Apple for support and service

Also…

If your Apple ID is locked or disabled - Apple Support

We are fellow forum members like yourself and can only point you in the right direction…you may get in touch with Apple through links above for their assistance.

~Katana-San~