Like the other reply said, your first step is to contact the seller. Explain your item is damaged. Do so immediately through ebay messages, there are time limits to consider.
Is the item ruined? Decide for yourself if it needs to be returned for full refund or whether you would be willing to keep it if compensated for the damage. If it has been ruined by the postal carriers, you will have to cooperate with a postal damage claim that the seller will want to initiate and don't throw out the box it came in yet. Photographic evidence may be required.
