Don't buy from them.  Non-responsive Sellers will only cause you further problems after you buy.  If they can't even get their ad right, how can they get anything else right?  Go elsewhere and save yourself a headache.

There is no point contacting someone at eBay, eBay staff have zero way of knowing what colour the item in question is, how could they possibly know? 

However, if the ad is misleading and the seller is ignoring you, why would you want to buy from them at all?

What is the item number?