Not to resurrect an old thread, but I just did this...
I was on Boost Mobile with a Lumia 635 for about 4 months. That was my first foray into the Wonderful World of Windows Phones. Then I saw last week that Sprint/Boost had dropped the 635. I also recalled some statements by the CEO Dan Hesse that they were bearish on Windows Phone and were not planning on carrying it. Then the official release of Windows 10 Mobile hit, and I downloaded Upgrade Advisor to see what my fortune was, "Sorry. No upgrade for you!" it said (paraphrasing, of course).
I read the writing on the wall and decided to pick up a $30 AT&T Lumia 640 from Best Buy. Decided to jump to Cricket. I had to call Boost in order to get my account # (tricky bastards), and we had an interesting conversation:
CSR1: Why do you want your account number? Are you planning on switching to another carrier?
Me: Yes, I am.
CSR1: Why is that?
Me: You guys don't carry any of the new Windows Phones.
CSR1: OK. Let me get you that account number. Please hold.
[Several minute hold. Someone else picks up, who I quickly realize is in the retention department.]
CSR2: Hello. Is that right that you are considering leaving, and you are interested in Windows phones?
Me: Yes.
CSR2: Was there anything wrong with your handset or your experience?
Me: No. It's just that I was interested in a newer Windows phone running Windows 10, and you guys stopped carrying any Windows phones a month or so ago.
CSR2: [typing away] Hmm. Yes, we did stop carrying them. Well, we could offer you a free Android phone, if that might change your mind.
Me: Uhm, no, thanks. I'm really interested in Windows Phone.
CSR2: Are you sure? We have several different ones you could choose from.
Me: No thanks.
CSR2: Which carrier were you planning on switching to?
Me: Cricket Wireless.
CSR2: OK. Let me get you your account number. . .. It is ##########. I hope you consider us again in the future.
Me: I very likely will... as long as you get some Windows phones back in your line-up..
BOO-yah. Slap, to their Windows hating faces!!
I've never known Boost or any other carrier to do cable-industry style retention moves, so this took me by surprise. It felt gratifyingly awesome to tell them that they are losing (at least one) customer due to their lack of support...