Verizon has struck back at what it calls a Netflix "PR stunt" that blames its network for poor video quality. In May, Netflix began testing an error message telling users that congestion with their ISP was hurting their service quality. "The Verizon network is crowded right now," said one message shown during buffering. But "this claim is not only inaccurate, it is deliberately misleading," says Verizon, suggesting that the choice was a political move meant to score points in the net neutrality fight. "It is sad that Netflix is willing to deliberately mislead its customers so they can be used as pawns in business negotiations and regulatory proceedings," it says. Here's its reasoning:

The source of the problem is almost certainly NOT congestion in Verizon’s network. Instead, the problem is most likely congestion on the connection that Netflix has chosen to use to reach Verizon’s network. Of course, Netflix is solely responsible for choosing how their traffic is routed into any ISP’s network.

The issue in question isn't that a network was crowded, it's which one was crowded. While Netflix's statement implies that the problem lies with the "last mile" of Verizon service, Verizon says the issue is really Netflix's connection to that last mile. This segment is the subject of a power struggle between Netflix and ISPs, who have been negotiating over how the service can reach subscribers. Netflix has struck paid deals with Comcast and Verizon to connect directly to their networks, rather than using a third-party service to send data, and Verizon rightly points out that it's playing fast and loose with the limits of the "Verizon network." "It would be more accurate for Netflix's message screen to say: 'The path that we have chosen to reach Verizon's network is crowded right now,'" said the post. But given that Verizon itself has control over how to manage and upgrade those connections, there's some hair-splitting going on from both sides.

According to Netflix, Verizon and other ISPs are allowing congestion to build up at certain connections in order to assume a gatekeeper role and charge "tolls" for infrastructure upgrades. After Netflix paid Comcast for a direct interconnect, its performance improved dramatically and rapidly. According to Netflix head of product Neil Hunt, "There is plenty of capacity, as demonstrated by the fact that after we reached the deal with Comcast, they put online a lot more bandwidth rather quickly." The ISPs have maintained, on the other hand, that there is an open market for connections and that content companies have plenty of choice when it comes to how and where their data gets to their last mile networks.

Verizon is also right to say that these interconnections aren't technically covered by the policy of net neutrality, though Netflix CEO Reed Hastings has disputed this, unsuccessfully asking the FCC to expand its rules. The real problem is a lack of transparency around the causes of congestion and the cost of upgrading the infrastructure, making it difficult to tell what rules might actually be necessary. What's particularly interesting about this fight is that it comes supposedly after the two companies have resolved their differences. But a source familiar with the situation told The Verge that Verizon has been slow in improving quality, leading Netflix to take a public shot. Netflix's snarky messages to Verizon customers suffering through video buffering have a two-fold purpose: to prod Verizon into quickly and thoroughly improving its connections as part of the paid deal and to move the political football in the ongoing debate over net neutrality.

Ben Popper contributed to this report.

Correction June 4th, 2014 3:40PM: An earlier version of this report said that the testing had begun on June 3rd; it's actually early May.