This is a phishing scam coming from Austin Texas. The shadowed the Apple Inc. Customer Support number in an attempt to gain access to your Mac and your Apple account. How they know what type of Computer system you have is not known,so that part of the Scam is likely a 50/50 hit or miss for these Criminals. Could be that they hacked a database base of Apple Customers and your number was on that list.
This is all the information I could obtain after a Google search regarding this false number.