Dan, if I was in your situation, I wouldn't bother going thru Euro-Pro, expecting them to honor the seven-year warranty. They will most likely tell you that since you bought thru Ebay that you have no warranty, since you purchased thru an unauthorized channel. If you had obtained this vacuum directly from Euro-Pro or had bought it from a department store, & it was NOT a refurbished model, then you would have a case to approach them for warranty repairs.
I am willing to bet it's an issue with a circuit board inside the powerhead that's causing the trouble....the powerhead is obviously receiving power if the lights are working. It could also be a loose micro connector or micro receptacle that's causing the issue, try opening it up & see what you find. What you could do if the vacuum is unrepairable, is to buy the identical model thru a dept store....if you like it, then keep the one you bought on Ebay for a parts machine. If not, then re-sell your Ebay Shark as a parts machine, explaining in the description that the powerhead does not work.
Best of luck....Rob