求助：ebay购物没买成，还要上法庭?

一个半月前，媳妇再ebay order 一个电子琴给我，付款方式是personal money order, 450$.
money order寄出后卖家不回email，从ebay得到的买家电话是空号。咨询ebay的结果是提供了一系列options, 其中建议stopp payment if can. 于是在money order寄出10天后stop了payment(居然还没被兑现！）并email通知了卖家。
今天收到DALLAS CHECK CASHIERS 的信。说他们: clearly qualifies as a "HOLDER IN DUE COURSE" as defined by the U.C.C.3-302, as a "Holder who takes the instrument a. for value:
b. in good faith
c without notice that it is overdue or has been dishonored or of any defence against or claim to it on the part of any person

In a situation where a check is reported lost and replacement is reissued, if the orgininal check resurfaces and is cased by the named payee, then the maker of the check is responsible for payment of both checks issued.
OR,
If the payee was not entitled to the proceeds of this instrument then it should not have been tendered to him. In effect, there is no legitimate basis for Dallas Check Cashiers to stand the loss for your error. If you will consult your attorney, they will inform you that this is a correct statement of the appicable law, and that you are without defense of our claim.

让我们十天内寄$450+$25 fees 给Dallas Check Cashiers. 否则，要告我们。

如果那个卖家是真的还有同样的东西倒是无所谓，但现在都好像和他没关系了。好像我们欠了Dallas Check Cashiers钱！！！

请各位兄台给我参谋一下，我有没有这么倒霉？
我媳妇刚生孩子，才满月。电子琴实际是我们给儿子买的。我还真担心那天警察来敲门，把我媳妇带走了，正在想把钱寄了得了，算我倒霉。