The primary is over, but Alexandria Ocasio-Cortez and Rep. Joe Crowley are still clashing

The claim set off a jarring an unexpected round of recriminations, especially surprising given how quickly the heat around their race seemed to dissipate after Ocasio-Cortez defeated Crowley in a New York Democratic primary last month.

On the night of the vote, Crowley, who has served in Congress for two decades, picked up his guitar and dedicated Bruce Springsteen's "Born to Run" to Ocasio-Cortez. Speaking to CNN's Erin Burnett a day after her stunning upset, Ocasio-Cortez, a Democratic socialist and emerging hero on the progressive left, said she was moved by Crowley's gesture and praised him for "[handling] that moment with such grace."

Asked then if they had spoken, Ocasio-Cortez laughed. "We're looking for [his phone number] and we've been reaching out," she said. "I greatly look forward to having that conversation."

But that conversation never happened, both campaigns said Thursday, as lingering tensions between them spilled out in the open on Twitter.

In a pair of tweets, Ocasio-Cortez said Crowley had "stood me up for all 3 scheduled concession calls," then claimed the party's fourth-ranked House member was "mounting a 3rd party challenge against me and the Democratic Party."

Crowley shot back, in a series of posts, maintaining that he would -- as promised when asked about the prospect of his losing during their primary -- support her in November. He also laid the blame for the lack of direct communications on the Ocasio-Cortez team.

"I'd like to connect," he wrote, "but I'm not willing to air grievances on Twitter."

As part of an endorsement that came before the primary, Crowley will be on the Working Families Party's ticket in November. Bill Lipton, the WFP's state director, confirmed that Crowley has, as first reported in the New York Times, refused to go forward with the process that would see his name removed from the 14th Congressional District ballot.

After Crowley responded publicly, calling the necessary maneuver to remove his name from the WFP line a form of "election fraud," his spokesperson also accused Ocasio-Cortez, a 28-year-old first-time candidate, of misleading voters about the nature of her concerns.

"She's upset that Joe's name is still on the ballot in November and is trying to intimidate and bully him into doing something he believes is unethical," the spokesperson said. "He's not running at all. He has no intention of running. He supports her vigorously. Words matter -- which is why it's completely unfortunate that she's chosen to lie."

Ocasio-Cortez spokesman Corbin Trent said a growing "sense of a lack of willingness to work together," along with Crowley's refusal to take his name off the Working Families Party ballot line, had largely prompted the tweets on Thursday.

"When you combine all those things together, and you know that you've got a candidate (in Crowley) that didn't really see this coming right and and this totally changes the trajectory of his future, you worry," Trent said. "We literally just sent a bunch of staff off to other campaigns."

Lipton strongly rejected Crowley's suggestion that the WFP, in potentially employing a mechanism used by smaller parties to change positions after major primaries, would be doing anything unethical or unusual.

"The Queens County Democratic leaders are the masters of electoral manipulation," Lipton said. "There's a well-known process for moving candidates from the ballot and they are refusing to show the WFP and Ocasio-Cortez that respect."

In the aftermath of her shock victory last month, Ocasio-Cortez has become a national political figure and is using her status to boost other insurgent candidates. She has also been attacked on the right and, in some cases, been the subject of pushback from the Democratic establishment, who worry that her politics -- should they pick up steam in other districts -- could endanger the party's hopes of flipping the House this fall.