I have the same problem. I bought a student version, registered it and sent the documents to get a key, and now fourteen days are gone, and I didn't get any answer. On the box you can read that the answer will take 1 to 3 working days, otherwise you shall contact the support. But the menu of the support doesn't help with this problem! The same happens if I call a phone number I found on the page of Adobe.
Can somebody tell me a possibility to really get in contact with Adobe in this case?
Thanx for an answer,
I had already followed the steps on this page, but one remark I found now is new for me: On the Programm box they speak from 1 to 3 days, on the page you recommended me thy speak about 2 to 30 days.
That's a little different.;-(( If nobody has another idea here, then I fear I have to wait some days or weeks longer.
In the meantime, you can download the trial version of Lightroom 5.6 and install it. You will be able to use it for 30 days. Then, when the serial number arrives, you can activate the trial version with that serial number without having to reinstall anything. And you will have full use of Lightroom during that 30 day trial. However, this assumes that you haven't been using the trial version up until now. If you have already used up your 30 day trial, then you will just have to wait for the serial number.
I'm quite surprised that it is taking so long to receive the number. When I activated my academic version I received the serial number within about 5 min.