Hello, This Is Mr. Bobcalling

Me: “Hello, you’ve reached [store]. This is Liz speaking. How may I help you?”

Customer: “Hello, Lizspeaking. Do you have this in stock?”

(I have no idea how to gently correct him, so I let it be and put the item he wants on hold. He then comes in later to pick up his item and approaches my coworker.)

Customer: “Are you Ms. Lizspeaking?”

Coworker: “What?”