Long time iphone user coming back to android. The advice I'm giving to somewhat dependent on what customer service rep one gets. I added a line to keep my unlimited data, switched phones once added and suspended the new line. Fortunately, my rep told me that once the 14 days were over, I can assume the new line( with contract ) and keep my unlimited data. Essentially I am taking over the contract and keeping my number. Let me know if anyone tries this and is successful.