How to make Formal Complaint against Apple Support?

There is no web or email link for reporting support issues. You can also call Apple HQ but I suspect a well-composed business letter will be more effective.

PS: Apple are not here. This is a forum of end-users s we cannot give an "official" answer.

Welcome, Gemall, to Apple Support Communities!

To file a Formal Complaint, I would expect you would write a letter to Apple’s Corporate Address.

See Contacting Apple.