how can i remove my billing address

Start here:--> Change, add, or remove Apple ID payment methods - Apple Support

If you get no help, contact iTunes Store Support Team using this link:--> iTunes Store & App Store – Get support for various issues, choosing: your country, then Apple ID, then iTunes & App Store. If your problem is not among the options shown there, tap/click on the option “the topic is not listed” and describe your issue.

Regards

Giulio