To the right of the purchase you have options to take action

Given it is from China then just open a dispute for item not as described if they sent the wrong one.

If you contact the seller they will just make promises to trust them till it is too late to take action.

If the return address is China and the purchases says item location is Australia then call ebay as the return cost will more than likely be more than the cost of the item.

Some things you just do not buy from OS.

If you got what was ordered but you ordered the wrong size then there is nothing you can do really.