The Los Angeles Unified School District is demanding a multi-million dollar refund from Apple Inc., after canceling a troubled program to give iPads with curriculum software to each of the district's students.

The school district, which is the second-largest in the nation, informed Apple that it will not accept further deliveries of iPads or pay another dollar toward the program, which was supposed to provide each of the district's 650,000 students with an iPad loaded with educational software from the Pearson Education company, at a cost $1.3 billion. And, underscoring the failure of the technology initiative, the district's school board this week authorized the purchase of new textbooks.

“While Apple and Pearson promised a state-of-the-art technological solution for ITI [Instructional Technology Initiative -- the district's name for the iPad program] implementation, they have yet to deliver it," David Holmquist, the school district's attorney, wrote in a letter to Apple's general counsel.

Holmquist said that the school district was "extremely dissatisfied" with the curriculum delivered by Pearson. "As we approach the end of the school year, the vast majority of students are still unable to access the Pearson curriculum on iPads," he wrote.

The school district had signed a contract that called for Pearson to provide English and math lessons to students' iPads, as a subcontractor to Apple. A three-year license to use the curriculum added about $200 to the $768 cost of each iPad, the Los Angeles Times reported.

The deal has, however, been a source of controversy since it was signed in 2013. In the months after the agreement was signed, the district found that a third of the 2,100 iPads distributed during the pilot program had gone missing, and that many students had disabled the browser and app limitations imposed on their devices, according to Ars Technica.

In addition, the FBI is investigating whether Pearson had an unfair advantage in the bidding process. An investigation, published by California public radio station KPCC last August, found former superintendent John Deasy and top district staffers had close ties with Pearson executives before the contract was awarded.

The school district reportedly purchased Pearson's software despite the fact that it was unfinished when the deal was signed. Teachers subsequently said the lessons that were available on the portable computers had errors, were missing material, and lacked many of the interactive features the vendors had promised.