Many were accepted, with a phone.

Over 1,500 of the claims were refused, but just as
Rick Rojas, reporting for The New York Times:

That it was under warranty, and not long after and device wouldn’t turn on, there came a genuine replacement in the email. It was a
scheme that prosecutors said two college students in
Oregon replicated on such a scale as they shipped in hundreds of counterfeit phones that it amounted to nearly $. […]

Records provided to investigators by Apple enabled them to connect
 ★ 
The con was simple
All of them indicated”No
Power/Wired Charging Issues” because the main reason behind the claim.

I don’t know these men thought they’d eliminate this, but I have guessed they’d have already been flagged a lot sooner than 1,500 replaced iPhones and 3,000 attempts.