Why did my delivery date get postponed?

I ordered a iPhone 6, 64 GB, Gold on Nov, 11 and the estimated "Available to ship" was 7-10 days. Which would have put my shipment time frame to Nov, 18 - Nov, 21, but it wasn't the case. It was Nov 21 - Nov 26. Now the shipment got postponed to Nov 26 - Dec 2. This is ridiculous. I don't even think contacting customer service would help. I am very disappointed in Apple. What are they doing...