Dealing with Google Checkout Merchant support

Some PostJobFree users are getting "Your cart cannot be processed because it contains more than one digital item." error when they try to subscribe for Premium Membership.
Googling the errors shows that this bug is about two years old

So I opened a ticket.
Here are excerpts of my conversation with Google Checkout Support in the course of days and weeks:
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Google Checkout support: I understand your buyers are unable to complete purchases.
...
Google Checkout support: One of the limitations of the currently mobile buy flow is that only a single digital item may be purchased at a time.
...
Me: Do you log more detailed description when you show that cryptic error message?
...
Google Checkout Support: We typically log errors in the Integration Console, but I don't think this error was logged there.
[Me thinking: "You cannot even log your error messages?"]
Google Checkout Support: I've only seen that error displayed on mobile devices. Could they have
been purchasing from an iPad or Android Tablet?
[Me thinking: "Why can't you trace it yourself?"]

Me: I explicitly asked him if it was mobile or desktop and he replied "Desktop".

Google Checkout Support: Try asking him to try a different browser. Also screen shots will help
tremendously in debugging as to the best of my knowledge that error message will not be logged.
[Me thinking: "Great. Now you, tech guy, is asking my non-technical users to do non-trivial exercises just because you could not setup proper logging on your system."]

Me: This is an error that happens with another customer.
[Attached screenshot of user's browser screen when "Your cart cannot be processed because it contains more than one digital item." happened again.]

Google Checkout Support: That's odd are they modifying the user-agent? The /m/ in the URL
indicates that they're reaching the mobile buy flow.

[Me thinking: Google Checkout defines that URL and sending it to me. Who if not Google Checkout Support can find out why that URL was generated?]

Google Checkout Support: One current limitation of the mobile buy flow is that only a single
digital item can be purchased at a time. We're working on improving the
buy flow, but the current work around is to specify the item as a physical
good.

[Me thinking: Yay! At least they have a workaround!]

Me: Can you guestimate when mobile workflow would be fixed in Google Checkout? Is is about weeks, months, or years ahead?

Google Checkout Support: It'll likely take months before the update is released. I'm honestly
don't know why the user is being redirected to the mobile version.

[Me thinking: That's really good to know.]

Me: Could there be any consequences if I sell digital subscription as physical good?
Google Checkout Support: Ah yes you were specifying a subscription. Defining the subscription as a physical good would probably work just as well. I don't think there are any compliance consequences.

Me: Thank you - we'll try to switch to using "Subscription for physical good" option in order to overcome that disappointing error.

Google Checkout Support: Yeah it's quite odd. Let me know if you ever figure out why they were being redirected to the mobile buy flow.

Me: PostJobFree redirects users to whatever "redirect-url" element
contains in Google Checkout response XML.
I may try to log these URLs or even whole response XML.
Would you like me to do that?

Google Checkout Support: [no reply]

[Me thinking: I guess Google Checkout is not really interested in troubleshooting their bugs.]
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