I’ve just received a receipt for $59.99 for annual membership in the APP STORE. What’s this all about ?

See the following instructions. They include information on contacting Apple Support if the other steps don't help: If you see 'apple.com/bill' or an unfamiliar charge on your statement - Apple Support

If the only indication of the charges is from an email or text, be aware that it may be a phishing attempt to get you to log in to a site that appears to be Apple and divulge your password or credit card information. See: Recognize and avoid phishing messages, phony support calls, and other scams - Apple Support

and Identify legitimate emails from the App Store or iTunes Store - Apple Support

Unless you see the charge in your payment method's monthly statement its very likely a scam to get you to give them your details.

If no evidence of this charge exists on your Apple account or statement you can consider it a scam and forward it to Apple at reportphishing@apple.com