eBay

I have a seller trying to bill me another 6.60$ for shipping after I paid for the item. It weighed more than they thought

I am returning a purchase and I mailed it back to the seller by usps priority mail before I knew I needed a shipping label from ebay and I can't find a way to contact ebay about it, what do I do ?

I am returning a purchase and I mailed it back to the seller by usps priority mail before I knew I needed a shipping label from ebay and I can't find a way to contact ebay about it, what do I do ?