On Thursday, T-Mobile disclosed a security breach that impacted some of its prepaid customers in the United States.

The company told Bleeping Computer on Thursday that a “small number of customers” were affected by the breach that was discovered earlier this month. According to T-Mobile, customer names, addresses, phone numbers, account numbers, rate plans, and plan features were all left exposed. More sensitive information like passwords, financial information, or social security numbers were not affected.

“We truly regret that this incident occurred”

T-Mobile told the impacted customers this week that its cybersecurity team “discovered and shut down malicious, unauthorized access” to their accounts. Shortly after, the telecommunications company notified law enforcement of the breach.

If your information was breached, T-Mobile should have sent out an SMS today to notify you, but if you have switched providers or numbers, you may not have received it. You can reach out to T-Mobile at privacy@t-mobile.com or by calling 611 to verify whether your account was affected.

“We truly regret that this incident occurred and apologize for any inconvenience this has caused you,” T-Mobile said in a statement.

In August 2018, T-Mobile was hit by another data breach and the account information belonging to close to 2 million customers was stolen by hackers. Account details like phone numbers and email addresses were breached, but no sensitive information like social security numbers were compromised.