You can try to go to your correos post and tract there, may be you will see the information that your parcel was hold by customs. Only the post office can see details. Other website can not see more
I have the same problem, since last month my parcel left China and they are still transit forever. I see from the post that either the parcel was hold at the customs or still in transit in the third country. I don't know yet. Tomorrow have to check again. If you don't see any information for 30 days after the last information since your parcel has been left, you can open depute and request refund as the item lost.