When trying to purchase lunchboxes on my android devices (Samsung Galaxy S6 Edge, Nexus 7 Tablet) I am getting an error message.

Error while retrieving information from server. [RPC:S-7: AEC-0 LFJQ-2URX-M4TU6]

The same error message is experienced on my colleagues phone and device. Living in Germany with O2 as my cellphone provider. I have attempted to relog into Google play services, re-installed Fallout on my tablet including buildling new vaults and I have attempted to purchase products on other applications without hassle or problems. At this stage I feel like it's a purchasing error within Fallout itself, I would like to take advantage of the current sale, but I cannot, please help.

I should also add that I have tested on WIFI and data connections and there is no problem with connecting to Google services or other applications.