i'm being charged for downloading free apps and i cannot download even instagram for free. please help😿😿

If your payment method cannot be verified, it will ask you to correct it and try to verify it again.

Verifying will involve placing a temporary authorization hold. This hold is not a charge for any app, and should be reversed once the payment method can be verified.

Note, you cannot make use of the App Store and iTunes store services including downloading free apps if your payment method is not verified.

About payment card authorization holds in the iTunes Store - Apple Support

You will not be charged for free apps, or app updates, but your Apple ID payment information must be up to date.

If you do not plan on buying any apps, you can set your Apple ID with None as payment method.

Create Apple ID with None as payment method

https://support.apple.com/en-us/HT204034

Without knowing any of the specifics, I suggest contacting Apple directly:

Sign In - Apple