and, look for a lawyer just in case.
Meanwhile, I answer them, by mail. [US mail], in writing rethinking the facts – your agent [post office] He left the article without obtaining a signature even though they had paid for the required signature. I will continue to point out that the violation of the terms of your agreement at the post office makes the post office responsible for the consequences, including this theft of the merchandise. It follows that, if they sue someone, it must be the post office.
You can also suggest that the delivery agents change, since the post office is simply not doing the work for which they are paying.