Apple has banned my PayPal - because I complained to PayPal and not to Apple

Whoever told you it was banned was either mistaken, or lying. Apple does not ban payment methods for missed payments. It only restricts access to store services until payment is completed.

If you block a payment directly from the payment method, rather than through Apple, then the charge remains pending, and won’t let you use the store services until its completed.

You will need to complete the payment either by releasing it from Paypal, letting it be actually charged, or by adding a new payment method that can be charged.

Once the payment is complete, then contact iTunes billing and request a refund. If it was charged after it was cancelled, then they should have no issue refunding it.

See here: iTunes Store - Contact Us - Official Apple Support

Again, not banned. Apple does not ban payment methods. Since you wen through Paypal Apple has no way of knowing, and and is still expecting payment. Since Paypal blocked it, and refunded you the payment to Apple is likely still pending on your account.

If it can’t get through with your Paypal account, you may need to use a different payment method to get it cleared, before you n use Paypal again.

Again. So its clear: Apple does not ban payment methods. Period. Whoever said that was mistaken or lying. It not unheard of, for 1st tier Apple support to just make this up on the spot, to be able to move on to the next support ticket quickly.

my suggestion, go back into your account, and see if you can get the payment completed. Make sure you contact Paypal and tell them to let the charge through.

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

You can add a different payment method to clear the charge, and them try to re-verify Paypal on your Apple account.