Verizon Wireless has agreed to forgive a $20,300 bill sent to a nonprofit that was accused of using 1.3TB of data from one phone in just 10 days.

Horizon Education Centers of Cleveland, Ohio fought Verizon for three months over the June 2016 bill before finally complaining to The Plain Dealer of Cleveland and the Federal Communications Commission. The newspaper has been publishing a series of stories about surprising data overage bills that cast doubt on the accuracy of Verizon's data usage meter.

"In the most dramatic case, Verizon on Friday agreed to wipe out a $20,300 bill to a Cleveland non-profit for supposedly using 1,300 gigabytes of data in one month," The Plain Dealer wrote today.

Horizon has 49 phones and iPads on its account, but Verizon claimed that just one phone used the 1,300GB in 10 days during May, a previous Dealer article said. Using that amount of data on a phone would be extraordinarily difficult; even streaming Netflix at its highest mobile quality for 10 days straight would account for "only" 720GB. Getting over 1TB would probably require sharing the phone's Internet connection with a computer and downloading large files.

"Verizon originally claimed Horizon's employee took out the SIM card and shared it with other cellphones" but later "backed off of that claim and blamed the usage on something else" and forgave the bill, the Dealer wrote.

Although the employee in question uses social media frequently, they had never used much more than 10GB in any single month during the prior three years. This is according to Horizon Education Centers Executive Director David Smith, who also told Ars today that it's "impossible" for the employee to have used 1.3TB in 10 days. He believes Verizon's data meter counted incorrectly.

Horizon had a 60GB shared data plan at the time of the unexplained overage, but the nonprofit has since bumped its plan up to 80GB a month. One month before the 1.3TB reading, Horizon used just 54GB; since that giant bill, Horizon has used between 27GB and 57GB a month, according to numbers Smith provided to Ars.

Even when Verizon finally canceled the bill last week, the company didn't admit any fault in its data meter. "They were claiming something about media content management around video from external sites like Facebook and YouTube," Smith said. "These sites were pulling massive amounts of data to search and connect pieces and parts of videos and other content. As I told The Plain Dealer, I was happy to have the credit and did not question or debate with Verizon."

We contacted Verizon this morning but haven't heard back yet.

The Plain Dealer previously wrote about a $9,100 bill charged to a Florida woman, which was also waived by Verizon. The newspaper's investigations may have led to an increase in complaints to the FCC; customers filed more than 2,000 billing complaints against Verizon Wireless in September, about a tenfold increase over previous months.

Carriers are required to respond to FCC complaints within 30 days. The FCC doesn't usually intervene in specific cases, but the complaint process can help customers pressure ISPs when they believe a problem isn’t being addressed properly. In addition to Horizon, The Plain Dealer's latest story details a number of Verizon customers who disputed mysteriously large data overage charges, some of whom were able to get refunds or credits.

Verizon recently introduced a "safety mode" that throttles data speeds instead of automatically charging customers extra when they go over their data caps. But many customers are still on plans without this feature.

UPDATE: Verizon responded to Ars, saying that the charges to Horizon Education Centers were "valid." However, Verizon said, "we recognize the important work Horizon does as a nonprofit; forgiving their bill was the right thing to do." Verizon also said it has not found "any widespread issues" with incorrect data charges, "but we always keep an eye out for that possibility."