You can only confirm that your caller was Sterling or one of its many other trade names. Third party collectors can easily pose as the creditor verbally. Complaints going back nine years frequently indicate that Sterling debt calls reach the wrong parties. They cannot all be victims of decoy phone numbers.
Try minding your own business. Prior complaints are not a fluke. Consistent reports on Sterling collectors describe the same bully tactics which would make them feel at home in any bogus debt shop in Buffalo or Atlanta. They are the kind state legislators thought of in those few places where collection practice laws apply to original creditors.
Innumerable wrong people have been targeted, including customers with never-late accounts, people who are not Sterling customers, and those who have never purchased jewelry from anywhere. I'm sure they are capable of paying their legitimate bills without your prodding.
That's the one truthful part of the comment. Sterling operates under maybe twelve or fourteen unique business names and several more which are variants. See the "Alternate Business Names" way at the bottom of their triple-B profile, below their hefty current complaint count of 1,526.