This is a call center with an autodialer that hangs up if one of its minions aka telemarketers isn't available when you answer. Excessive dropped calls are a sure sign of a scammer, and are also a prosecutable crime (if you can get the company's name and address).
Another sign is that the crooks who call our office daily trying to con us into a small business loan use the caller ID of "CUSTOMER CARE", as this caller did.
Beware!