When I've used Hermes labels provided by the retailer before, the tracking won't update after the 'on it's way', because I'm not the sender I guess. If you know the postcode it's going to you might be able to enter that to get more information but mine were always outside the uk so it didn't accept it.
It's not a standard consignment like if you send yourself by a parcel shop, if you try to contact them by phone or email, they recognise it's a big retailer and direct all support to them. Probably Amazon's returns are rammed, give it 14 days and ask Amazon.
Looking at my Amazon account the return is still showing as being at the first stage, waiting for the item to be dropped off. The good news is that following my contacting Amazon last week they have refunded the money to my credit card.