What was your original ship date? Also, what did you order? Size, color, regular or plus, and did you have other phones on this specific order? All of those factors can play a role in how soon you get your device.
why will it take 2 months to get my new phone iPhone 7 plus 128 gig jet black
That is an estimation on the date Verizon expects to receive that from Apple. Verizon can only send them out when they are made available by Apple. Of course, being an "estimate", that date can change at any time.