Here’s a sign of just how much burning hatred T-Mobile and AT&T have for one another: They’re willing to engage in a public social media fight over one single customer. The Next Web notes that AT&T customer Jay Rooney took to Twitter this week to voice his frustrations with AT&T and asked the carrier why he shouldn’t switch to T-Mobile to take advantage of its free international data roaming plan. AT&T warned Rooney that switching to T-Mobile would be “scary” and took a shot at the carrier’s much-maligned wireless network. T-Mobile hit back and asked AT&T whether its “kindergarten panel” wrote its jokes. In the end, Rooney said that he’d visit a T-Mobile store and would ask about switching to its services.