I agreed, just waiting the tablet is arrived or not first within 20days, since I had an experience that the tablet is in custom(China) and was waiting them around 1 month to get it!!!! As i paid by paypal and bought by ebay, they help me to claim this and I left the negative feedback to that seller. as all are the fault of the seller, you have the right to do it.Do NOT agree to just cancel the transaction. You will get your money back regardless, but if you cancel the entire transaction (and they will ask you!), you give up the ability to leave feedback.
hopefull it can help you.