Q Link Wireless, a provider of low-cost mobile phone and data services to over 2 million US-based customers, has been making sensitive account data available to anyone who knows a valid phone number on the carrier’s network utilizing their App that can be downloaded for free by anyone.
https://arstechnica.com/information-technology/2021/04/no-password-required-mobile-carrier-exposes-data-for-millions-of-accounts/