Sprint customers say an apparent data breach has exposed other people’s private information in their online accounts. TechCrunch spoke to one customer who said that more than 20 people’s names and phone numbers were revealed when they logged in. Others said they saw several numbers that were not theirs, with one adding: “I was able to click each one individually and see every phone call they made, the text messages they used, and the standard info, including caller ID name they have set.” Several others reported the same issue on Twitter. Sprint hasn’t commented on the apparent data breach yet—but one customer reported informing the company of the problem and being told by a representative that there were “several calls pertaining to the same issue.” Sprint is the fourth-largest mobile network operator in the United States and serves more than 50 million customers.