Is it better to call verizon customer service or go in the store?

I want to get the Iphone 5, i currently have the piece of *** Droid X that has recently broken. By broken i mean the screen has black dots from dead pixels. The phone also randomly shuts off and lags. I have got 3 replacement (Droid X) phones already and constantly contacted verizon. My upgrade is in January, but I don't want to wait. Will verizon let me upgrade if i'm 20 of 24 months in my contract? Is it better to call customer service or go in the store? What else should i do or say to get them to give me the iphone 5? Help!

Added (1). Really my choices are:
A: Iphone 5
B: Iphone 4s
C: Samsung Galaxy S III
What do you guys think i should get and why. Your responses will be greatly appereciated and taken into consideration on which phone i will get.

Call them first to see if you can save a triop to the store.

Okay for one the DROID x is very old… The iphone is the worst phone in existence and the samsung galaxy s3 is far far far better