If more than 45 days have passed, and you use Paypal to process your credit card payment, you can phone the 1-800 number on the back of the card and ask about a chargeback.
When a seller offers to send a replacement, don't accept. Demand (politely) a refund of your entire original payment. If you still want the item and trust the seller (read his feedbacks and Detailed Seller Ratings) you can re-order, starting the process from scratch.
You have 60 days to leave feedback. At that time, you will be asked to leave Detailed Seller Ratings. The normal rating is Five. The lowest Rating is ONE star. Sellers whose Ratings drop below 4.3 are severely restricted in their ability to list and to sell.