Did you register the software? Do you have proof of purchase?
If the answer is yes to either, contact Adobe support directly. Nobody here can help with this.
I have proof of purchase but apparently did not register it. Two hours
of waiting and then online chat with Adobe didn't help. I have tried to
contact the seller (Techsoup)
I also have a copy of InDesign 3 (with serial number) if there is a way I can do it as an upgrade to that product.
Do you mean InDesign 5 (also knows as InDesign CS3 released in 2007) or InDesign CS5 (also known as InDesign 7 released in 2010)? And similarly, in terms of your upgrade question, do you mean InDesign 3 (also known as InDesign CS released in 2003) or InDesign CS3 (also known as InDesign 5 released in 2007)? Clear as mud?
The bad news is that unless you registered the software with Adobe or the vendor you licensed the software maintained a copy of your serial number for you, there is not much that anyone can do to assist you.
Upgrades from InDesign 3 to InDesign 5 (or InDesign CS3 to InDesign CS5) are no longer being sold by Adobe or any authorized Adobe reseller. Sorry!
I mean CS3 (which I had as the whole suite) and InDesign CS5, which I got without the whole suite. sorry to be sloppy.