I bought an item (rice cooker) on Ebay, and received a lower end model than the one I paid for. I just sent the seller a polite message regarding the mistake. Should I give the seller a chance to get back to me first, or should I dispute the transaction with Paypal right away? I do not wish to come across as being overly aggressive, but given that the seller's stated that returns must be done within 14 days, I do not have that much time left either.