This is Rip. He babysits the rescues with his brother Samuel. The two boys and their sister were abandoned in a closed up apartment when the tenant was evicted. Luckily they were found early. Their sister went to another family.
As I read this, my thoughts are that he sold your receiver and there may be a paper trail on that s/n. Maybe he figured you didn't have the s/n and he could simply defraud usps to satisfy you.