Well more than likely it was a competor that got your listing pulled using ebays wishy-washy shoot first and ask questions later policy.
Unless you have a powerseller status, it will be kind of hard to get any kind of answer or result from ebay. However if you have found a product which you think is going to work well for you, I could suggest two things:
First start saturating ebay with emails about exactly why your listing was pulled and include a copy of the email from the dropshipper stating that you have permission to use their photos. It may take a ton of emails, but eventually they will get tired and answer you. Keep doing this until you get a resolution. 'the sqeaky wheel gets the grease'.
Second, order a couple of the items from the dropshipper and take your own photos. It never hurts to have a few on hand in case the dropshipper runs out of stock and sends you the dreaded 'on backorder' notice anyway.
Copyright is a very vague definition. It can mean anything from using a vero's photos, to using their descriptions of the product to selling the item without being licenced by the parent company..