Sent wrong item but they still wanted me to pay for it
This company does not provide a tracking number unless requested. Although they were fairly good at responding to communications, everything else was bad. They sent an item that was not as described and blamed it on a mistake at the warehouse. They didn't honor their "free returns" promise on their website or the guarantee of "get what you ordered or your money back." They offered me a small refund to keep the wrong item. I wanted them to send the right item or refund in whole, as stated on their site! Then they offered a refund that was a tiny bit bigger, and told me they only get a small profit on the item. I told them I didn't want the incorrect item and they told me I could send it back but it would cost a lot of time and money because it would have to go back to their China warehouse. I then opened a dispute through PayPal and they offered a tiny bit more again (still less than half the price I paid). I then escalated the case to PayPal and stopped responding to their emails. Then two days before the case demanded their response they sent me one last email saying: "Do you accept our offer?Because we may submit Paypal request to enter the return process, so there is no way to refund in the operation." I ignored and waited to see what PayPal would say. A couple days later PayPal closed the case in my favor and issued a full refund.
For the PayPal case I provided them with every detail; showing photos of: the web listing, their guarantees, screenshots of emails with the seller, and the item I received compared to the item listed.