Pop-up in CS6: it seems I have no choice but to purchase Adobe CC?

Hi,

October 2012 I purchased Adobe CS6 from a (Dutch) website which offers software for discount prices to students and teachers.

The day before yesterday I installed a system update (not particularly linked to Adobe or something). After doing this I wanted to use Photoshop (which was already opened) but when clicking on the PS window PS immediately 'got stuck'. Ultimately I Force Quit Photoshop.

After re-starting PS I got a pop-up offering me Adobe CC for a discount price. There were two buttons: one to purchase, the other one stated: 'continue trial' but was greyed out.

This is strange because I didn't purchase a trial version, I have worked with CS6 for nearly two years! I looked in my order history at the website, but nowhere it says it was a trial.

I could close the pop-up using the little x button, but it appeared again after restarting Photoshop. The same happened when starting Indesign and Illustrator.

So I couldn't use any of my CS6 applications anymore.

I deinstalled CS6 following the uninstalling instructions.

Then I tried to reinstall the package, but after typing in the serial number I got an error message stating the serial number was not valid and to contact Adobe Customer Service. The only option Adobe Customer Service gives me is to post the problem on this forum.

I searched on the Adobe website and Google but I couldn't find a similar problem.

Do you have any idea what the problem could be?

I know it looks like I unknowingly purchased a trial version but then again, why does it quit on me now, after 1 year 10 months?

Thanks in advance for your answer(s)!