Reliance Jio customer data was posted online by a website on Sunday. The mobile network has more than 120 million users in India, potentially making this the biggest data breach ever in India.

Users had first shared the URL of the website on Sunday, after which the news was picked up by other places. The website now appears to no longer be accessible. Reliance Jio though has said its customer data is safe.

The website had showed a customer’s name and their registered Jio phone number, Gadgets 360 reported. Gadgets 360 said it was able to verify the details of several customers on the site. In some cases, details of where the number was registered, and when the phone was activated were also available. In a few instances, the customer’s email address and/or Aadhaar number was also visible.

The website was registered in May 2017, and its IP address appears to be one in Mumbai.

Reliance Jio said, “We have come across the unverified and unsubstantiated claims of the website and are investigating it.” It added that the data appears to be unauthentic. “We want to assure our subscribers that their data is safe and maintained with highest security. Data is only shared with authorities as per their requirement.”