No seatpost = no refund, why should you be out of pocket and without the original item?
I am having similar issues with a guy who bought a Rear mech and shifter off me on Pinkbike.
He is in Denmark and postage has been about ten days now and still no got there he admitted something from Germany took 3 weeks.
He is pestering me constantly for updates which he has access too since I gave him the code, now he says it was for his wifes bike and he wanted it finished by the end of next week, so is there any way of cancelling it and getting a refund.
Erm no since it is literally somewhere between the UK and Denmark and he got them for a great price, maybe if he wanted them quicker he should not have ordered from someone in the UK.
These people seem to think pinkbike classifieds is like buying from a shop, you get all the benefits of returns, gurantees etc but is way cheaper.