What is the number to the escalation department?

Hi, I ordered an iPhone 6 online and it was shipped on Nove 13th. However, I never received it even though it showed as delivered.

I contacted the post office who told me to file a claim since there's an $100 insurance on it. I've also been calling the 800-331-0500 number, trying to get a replacement phone since Nov 14th. Three escalation cases have been created, but I receive no call from the escalation team. The represatative told me that the escalation department should get in touch with me within 72 hours and now it has been 15 days. 

I am wondering if there's a number to the escalation team so I can contact them directly instead? Thank you!