What is their handling time and when did you contact the seller?

What is the seller's feedback?

There are also sellers who don't mark their items as sent. Sometimes I have received items before they

were even marked as sent.

Your money is definitely not lost, as you can get it back if the item does not arrive by the estimated date. If you really concerned and want to talk to eBay, you can contact them via live chat from the help page, but I think you should wait a bit longer, and I don't think they can refund anyway until after the last day of the estimated delivery because the seller could have sent the item and not marked it as sent or maybe they were not online.