Hi there.
First time here, in the 10 blog.
When I was at the University, I got access to download and use Windows 7 Pro and also Windows 8.1 Pro for free, from a program called DreamSpark. I have original keys and what have you. Last night, I did a clean install of Windows 10 on a new SSD. The Windows 8.1 Pro product key from DreamSpark worked fine. Windows 10 activated automatically as well.
Recently at work, I have been told by a distributor that Microsoft ONLY CONSIDERS non-pirated software, those who present an invoice of purchase - which is not the case with DreamSpark. From what I've read in that time, when I downloaded Windows 7 or Windows 8.1, DreamSpark free software access granted lifetime use of the software to the student. That means, basically, my copy of Windows is genuine.
Now, I don't understand one bit when a vendor tells me that only ACTUAL PURCHASE INVOICES are the ONLY WAY to prove that it's your software! Been told that no keys, no stickers, no serials, all of this are virtual to Microsoft.
So, what do you guys think. Am I eligible to upgrade to Windows 10?
Why suddenly the concern ?
You have already done the free upgrade to Win 10 and activated successfully with the Win 8.1 Pro key.
Being a "distributor" does not automatically make him/her the pundit of the subject matter.
You already proved you were able to do it.
I agree your vendor may be trying to create additional sales or referring to a corporate environment.
I don't ever remember Microsoft asking me for some voucher to activate a License. If there is a problem with your situation, Microsoft has allowed the install and it is legal unless they tell you it isn't. Right now Microsoft is trying to get every computer they can to switch over to Windows 10, so there are probably quite a few allowances being made.
Distributor was full of you-know-what.
So it's all good then.
I get the idea of VARs pushing for more sales.
However, I have been told by an attendant at Microsoft Brazilian subsidiary themselves, that the factual invoices of purchases are the only thing to actually tell your licensed to use the software - for instance: If I buy a FPP product, if I lose the purchase invoice, I'm illegally using the software, despite having the genuine keys and media box. This may be an issue within the company, regarding licenses, varying according to countries. Those situations certainly violate DreamSpark scenarios, because they offer a lot of stuff over those channels. Who knows...
A legal license is a legal license and doesn't always come with any type of paperwork. You obtained your license legally, and are using it within the terms of the license itself. Nothing to worry about.