You say The product key written on it does not work
What is 'it' - is it a DVD or are you referring to a label on the laptops
As Office was pre-loaded it should be an OEM version with the product key on a Microsoft label attached to each laptop. Is that what you have.
When you cannot get on-line activation, what happens when you call Microsoft product activation. Have they told you that the key is not valid.
I also note that there does not appear to be a Microsoft product called Office 2007 Premium Home Edition
Look at this Wikipedia article
Also look at Microsoft's page about Certificates of Authenticity, to see if the product you have appears to be authentic.
If you have doubts about the product authenticity, Microsoft has a reporting system here.
I see that you refer to the Academic version in your title. As far as I know, there are no academic 'versions'. Academic 'pricing' is available from "Authorized Education Resellers" (AER).
If you got an Academic price from someone who is not an AER, then it is likely not a genuine product.