No, in other words, it works for me... and probably 99+% of the players; players that mybe haven't even checked these forums because they don't have the need to request assistance. Review the OP post... because thats what's all about. He's asking to force a GAME REMOVAL from the stores. Like those old cold war space denial politics... "If I cannot play, I'll try to force that nobody can".
I don't know whet device are you playing in, but as long as it's somewhat "common", there will be probably hundreds, if not thousands of people playing in that same device. And the vast mayority of those players aren't complaining... they don't have the need, they just play the game.
So, the players complaining are the ones that have issues... and those might be, let's say, 1% of all the players with your same device.
What's the most probable thing...?
- ... that there's an application issue common to your device model (something that "should" affect ALL terminals of your model, meaning that, sooner or later, when another player receives a phone call while playing the game, he should end up with a crashed vault)?
- ... or that there's something specific on the 1% of the devices that make the vault crash when a phone call is received, something that doesn't happen to the other 99%?
As you said, you want them to "fix"... but, to fix what?, when maybe they're testing "your problem" in one (or even several... "Hey Johnny, you have an iPhone 5? dl FoS an try this, please, seems there's a crash here but doesn't happen to us") of those 99% devices that don't crash the vault when a phone call is received or the game goes to background.
To know what to fix, you must be able to reproduce the same issue in your testing environment. You cannot fix what is not broken.
As I said before... that "lot of people" of yours may be just 1% of ALL people with your same device. But the other 99% is nowhere to be seen... because they don't have the reason to complain. Maybe you're absolutely right and nothing changed on your device... maybe it's something you had BEFORE you installed the game.
Systems test 101: you install a clean system. You install an app. You test it. It works. Release.
And the important word here is clean. You cannot control the myriad apps/UIs/frontends/facelifts that can be installed in a specific device, and the millions of interactions that those third party apps can make. Something as stupid as an antivirus/antimalware app can mess with your savefile, locking it for a scan when FoS shelter was tying to save.