eBay

I opened a dispute case because the seller sent my items to someone else and I never received them.Paypal refunded me my monies (for which I am grateful) however now I can't contact the seller or bid on his items. Why?

I bought an item and paid $12 for postage.It was the wrong size and I had to return it (I paid $20 to register and return it to the seller)Now I am told I have to pay for the postage again.Is this right?If the seller wants the sale and I want another...