There's no evidence in what you wrote that somebody sent you a
known bad part. You're making an awful lot of assumptions.

However, it is up to the shipper to make any damage claims with
UPS.

Sawney Beane wrote:
I seem to be dealing with an online retailer who has access to
parts that failed factory QC tests. His goods arrive with a note
saying if the part arrives broken, it's the fault of UPS and it's
the buyer's responsibility to contact UPS. Then he sends another
even if the buyer has repeatedly asked him not to, by phone and
email. As a result, he buys one part wholesale and bills the buyer
twice for his retail price and shipping. I'd like to know who to contact.