Is it possible to upgrade from Win 7 OEM to retail?

I sifted through my old emails and turns out that my key was identified as being an MSDN version.
Sorry for the confusion, I got OEM and MSDN mixed up. (it was over a year ago!)

The reply I received back then was something along the lines of:

--
"Opt for genuine Microsoft product offer. Kindly refer to the link below for more information.

Genuine Offers: How can I take advantage of Microsoft genuine offers?
'What are the details of the genuine Microsoft Windows offer?'

http://www.microsoft.com/australia/genuine/faq.mspx
--

That URL seems obsolete.
I'll do a little more digging around and if I can't figure it out i'll give them a call.

In that case, you might find this article of interest to you: Product Keys and Activation | MSDN Subscriptions

You need to go back to the local store and demand what you paid for. They already ripped you off by charging you $300, even if it is what legit...but it wasn't. If they do not honor the sale with a legit version, report them to Microsoft's Piracy division. You will get a legit key from Microsoft (assuming you have proof of purchase) and the local store...will be hearing from Microsoft.

Felii said:

I sifted through my old emails and turns out that my key was identified as being an MSDN version.
Sorry for the confusion, I got OEM and MSDN mixed up. (it was over a year ago!)

The reply I received back then was something along the lines of:

--
"Opt for genuine Microsoft product offer. Kindly refer to the link below for more information.

Genuine Offers: How can I take advantage of Microsoft genuine offers?
'What are the details of the genuine Microsoft Windows offer?'

http://www.microsoft.com/australia/genuine/faq.mspx
--

That URL seems obsolete.
I'll do a little more digging around and if I can't figure it out i'll give them a call.

I think this might be the link you need.

Microsoft Australia Anti Piracy - Make sure your software is genuine.

If a shop is selling TechNet keys it is a prosecutable theft. I'd let them know you're airing this in the top Win7 tech forum and intend to prosecute if they dont' make it good. They may give you an actual salable copy of Win7.

If not follow the suggestions to pursue it with MS and ask for their help in prosecuting for this theft. They have a program as mentioned to provide a free key when someone is clearly ripped off in this way.