T-Mobile suggests adding its port validation feature to all accounts. To do this, call 611 from your T-Mobile phone or dial 1-800-937-8997 from any phone. The T-Mobile customer care representative will ask you to create a 6-to-15-digit passcode that will be added to your account.

“We’ve included alerts in the T-Mobile customer app and on MyT-Mobile.com, but we don’t want customers to wait to get an alert to take action,” the company said in its statement. “Any customer can call 611 at any time from their mobile phone and have port validation added to their accounts.”

Krebs