Yeah obviously the red flag comes up - the Nokia company could most likely easily take the name away from you. Try getting a refund you don't want any trouble or if it's too late for a refund best thing to do is let this one drop.
It is not really that bad there are many trademark domains out there, for example nokia5800.net it is there for many years. It won't hurt unless you make false claims on the product. About the future, the domain has 368,000 EXACT searches monthly!
I Suggest you change your wordpress theme and not to post only youtube videos becouse the page gonna slowdown Regrats
Trademark is trademark. About the future, today Nokia 5800 is very popular but what will be tomorrow?