.How do I pay for my apple payment in Nigeria, I just want pay for Apple Music and they are declining the method of payment

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

Nobody here knows why Apple is declining the payment method you’re trying to use.

You’ll have to check with Apple and your financial provider about that.

Gift cards are an option, or by using a different payment card acceptable to Apple, most likely.

If you’re using an add-on VPN client when trying to pay, discontinue that and try again.