"In light of this, Verizon demands that Netflix immediately cease and desist from providing any such further 'notices' to users of the Verizon network," the company wrote.
The firestorm began a day and a half ago, when Vox Media developer (and former Washington Post staffer) Yuri Victor tweeted an image of Netflix's error message. The post quickly gained traction on social media, and prompted Verizon to complain in a blog post that the streaming video company was being misleading.
Evidently, Verizon thought Netflix wasn't taking the warning seriously.
"We further demand," Verizon's letter continued, "that within five days … Netflix provide Verizon with any and all evidence and documentation that it possesses substantiating Netflix's assertion to Mr. Yuri Victor that his experience in viewing a Netflix video was solely attributable to the Verizon network."
Netflix fired back that Verizon was working to suppress information concerning its network practices.
"This is about consumers not getting what they paid for from their broadband provider," wrote Netflix spokesman Joris Evers in an e-mail. "We are trying to provide more transparency, just like we do with ISP Speed Index, and Verizon is trying to shut down that discussion."
Here's a copy of the full letter.