how to file a complaint about iphone support?

I have spoke with 6 people in less than 48 hours. it took 45 minutes just to schedule a callback. that should have taken no more than a few minutes. my new phone is not working and they have no idea why. I cannot spend so much time on the phone with support. I asked to escalate to a supervisor and they said they do not have anyone that is available to listen to the customer's experience. I hope that the head of customer service would actually care what customers have to say.