President Donald Trump criticized AT&T in consecutive Truth Social posts Monday, writing that the country's third-largest wireless carrier "ought to get its act together."

The president wrote that he was trying to hold a conference call with "faith leaders," but that "AT&T is totally unable to make their equipment work properly."

The back-to-back posts came two weeks after the Trump Organization announced it had licensed the Trump name to a new wireless phone service, Trump Mobile, that also sells a $499 smartphone.

"If the Boss of AT&T, whoever that may be, could get involved, it would be good," he wrote. The chairman and CEO of AT&T is John Stankey.

"AT&T obviously doesn't know what they're doing!" Trump wrote in a second post minutes later.

"We may have to reschedule the call, but we'll use another carrier the next time," said the president.

The company responded to the White House via social media.

The broadside sent AT&T shares down on high volume temporarily before they bounced back.

Trump Mobile's "T1" mobile service will operate over all three major wireless carriers, according to the company's website.

The terms of the financial arrangement between the president's family business and the wireless service that licensed his name have not been made public.

The White House did not immediately reply to a request for comment from CNBC on Monday about the launch of Trump Mobile and the timing of the AT&T posts.

Trump Mobile is only the latest instance of the Trump Organization and the president's family using his political brand to promote new commercial ventures while he is in office.