Win 8 - problem with Windows license

Hello,

I have purchased the Dell Inspiron-15 laptop in October 2014.

The microsoft product - Win 8.1 Pro was sold along with the PC. This was a fully embedded verion, i.e neither Flash nor DVD containing the purschased operation system were supplied.

The service tag of the PC is: <ADMIN NOTE: Service tag removed per privacy policy>

These days all MS costomers having official version of win 7,8,8.1 are entitled to upgrade to windows 10. After having tried to upgrade my Windows to and all of a sudden I have found out that it can't be upgraded because I have a specific license named "Volume License", which has certain limitations.

I called Microsoft, they proposed me to contact "DELL" and resolve this problem by simply getting a proper product key, which entitles me to activate my Windows.

What should I do? Who I can contact about my problem?

Thanks,

Eli