I’m unable to make use of the iTunes on my iCloud to make any purchases

Any error messages given?

Are you using a payment method that is accepted in your region or country?

Payment methods that you can use with your Apple ID - Apple Support

If your payment method is not accepted, try the troubleshooting tips in this Apple help article:

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

Also make sure that your payment information is still correct and complete:

If you need to change or update your Apple ID payment method - Apple Support

Cyblize Said:

"I’m unable to make use of the iTunes on my iCloud to make any purchases: I’m unable to make use of the iTunes on my iCloud to make any purchases, why is it doing this way"

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Troubleshooting a Locked Account:

Contact Apple Support:

Visit this Link: If your Apple ID is Locked or Disabled - Apple Support

Why Accounts Become Locked:

When your iTunes Account has been disabled, and that often happens due to suspicious activity --- Perhaps nothing on your part. They disable it for no more than Security & Privacy concerns.

Possible Reasons Could Include: 

• Too many unsuccessful login attempts
• VPN (Virtual Private Network) usage
• Consistent transactions
• Session Times Out
• Disobeying Terms & Conditions

So...

To Re-Enable it:

As you might suspect, no one here would know the reason for this occurrence, of course. So, contact Apple Support. They’ll know why this occurred and will run you right through the fix.

Contact Apple Support:

• Contact Us - Choose Locations
• Proceed from there as necessary
• Note: Phone calls are taking a bit to go 
• through at the moment, due do lots of calls. With the Coronavirus Pandemic, many are at home at the moment, with much time on their hands to contact Apple. So, just stay on the line, and you will get through :)