Although I have no experience with the Google Play Store store, I am surprised to hear that there is no escalation path for front-line CSRs: any call centre I've ever seen has at least a second tier support queue, if not a Customer Relations department to which customers such as yourself can be escalated.

My suggestion would be to firmly insist on speaking with a Supervisor or the Customer Care Department. I'd be very shocked if the Google Play Store actually didn't have an escalations group.