在ebay上收到買家如此答復，我該取消訂單并退款嗎？

今天一早收到客戶的信息：
Hello!
We ordered and paid for this last night. We accepted your counteroffer too quickly, and it's unfair for $27 even with free shipping. We found another one that is up for $17 with $3 to ship it. We were going to cancel our order, but we chose to write to you instead and if you reconsider our offer for $24, we'll keep our deal. If you decline this, we'll cancel this order and buy it from the other seller tomorrow. Thanks for your time. We'd rather not cancel it from you, because we want to keep our deal with you for $24. We'd prefer if you stuck to our first deal. It is Sunday and it is almost 1 PM here. Please reply to us as soon as possible. Thanks again.
大致意思如下：
這款產品$27包郵還是太貴了，我昨晚確認的太快。后面又找了一家包郵$20的，所以想跟你取消訂單。但如果你能接受$24的價格，我們可以重新考慮在你這邊下單。請盡快答復。
交易都結束了，我已無心再跟他們討價還價，因為訂單生成，款都付了，所以他們要如何變更價格呢？不想收到客人的差評啊，該怎么做才對呢？