I'm using Google Wallet for Digital Goods (in Sandbox Mode) and it worked fine for month or two, and information on the database was updated accordingly. Recently, however, the purchases were completing, however the database was not updated.
For debugging, I deleted the postback script from the server, but very strangely, Google keeps completing the purchases even though the postback script no longer exists!!
So now every purchase goes through no matter what!
Google claims it was successful within the iframe (which pops up on the client to initiate and complete a purchase).
I'm using the sandbox credit card.
Is there a bug in Google's code?
I found the problem.
Somehow, the postback url field inside the sandbox settings page was deleted.
I had set it correctly some time ago but for some unknown reason it was missing.
It seems from this that Google completes purchases when no postback is specified.
-- dragonfire