I was gonna say "you're wrong" but that just didn't seem to cut it.
Backing up your savegame is discussed in much topics, but as your Google seems to be broken here you go:
Get into your file system (depending on your manufacturer you might need to get one from the Google Play Store, like ES File Browser) and go to
/storage/sdcard/android/data/com.gamesas.falloutshelter/files/VaultX.sav
where the "X" in VaultX.sav is the number of the vault in question from top to bottom in your savegame list in-game (so 1, 2 or 3)
Copy and paste that daily/every other day to a safe location or email it for all I care, but that way you'll lose little progress and/or boxes.
If you want a refund because you didn't receive what you purchased or your savegame is corrupt, follow the trail Bethesda and Google left you, you'll end up here:
https://support.google.com/googleplay#topic=3364260
On that page, drop down the "refunds and returns" -menu
in there "problems with in-app purchases"
In there, go to troubleshooting first, or if you already tried every trick/option in the book, go to "option 2"; contact support
That link will get you to a form you need to fill out, including your receipt number from the purchase you made. Have a copy of your savegame nearby as well to prove that it is actually broken.
State clearly what the problem is and as always, stay nice.
Haven't seen a single person come back empty handed (other than not filling in the form properly or not at all....)
Either use the refund to restart or don't. I don't think I will care more or less about it... (hint: I don't
)
Thinking of "we need a fix" gets me riled up easily. Objectively though, looking at numbers, there is only a very small percentage of users that have a corrupt savegame or have errors otherwise. Giving those people their money back is probably a more cost-effective way to deal with the situation currently. Therefore, "threatening" Bethesda to not play it might be considered a calculated risk they are willing to take.
NOTE: That is my personal opinion on the situation as it is, I have no sources to back up that claim in this occasion, other than looking at history and economics.
This should help you a bit... have a nice day!