iPhone headphone socket

Received my new iPhone 6S Plus from Apple yesterday, to find the headphone controls do not work. The volume controls do not operate, nor does the on/off button. (Yes, I have tried with other Apple headsets.)

I can see from the Internet that this is a known problem, yet it seems Apple are sending out faulty phones regardless.

Online chat seems to be offline, and the telephone messages say they are too busy and to call back later.

This is not at all the service we expect from Apple.