Since this is an open forum, not Adobe support... you need to contact Adobe staff to help
Adobe contact information - http://helpx.adobe.com/contact.html
-Select your product and what you need help with
-Click on the blue box "Still need help? Contact us"
-or by telephone http://helpx.adobe.com/x-productkb/global/phone-support-orders.html
You can buy the promotional offer but it is advisable to get them registered under different Adobe ID (Eligible for students)
I contacted Adobe Germany today and they confirmed that you can still get the introductory offer for the full CC after you had subscribed to the Photography Cloud.
You will need to cancel the present CC & repurchase, the cancellation fee for such issues are also waived off.