GI's response to my last support ticket:
"Our engineers are well aware of the issues with searching items for a Treadmill which can only be obtained from the Training Center which, in turn, will appear only after the first rocket launch. So we have got something like an endless circle here and at the moment the necessary items can only be found in friends' Training Centers. The developers have already detected the root of the problem and are taking appropriate measures to troubleshoot it. The same with the username issue, which in fact was thoroughly investigated, and we believe the next update will finally fix it as the developers seem to have found the proper solution. The Airport City on one of our support team's iPad has the same username trouble, to be honest, so we are looking forward to the next release as well as you are.

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