Unable to validate T-Mobile Rebate Card

Received Email from T-Mobile to activate a rebate:

https://login.northlane.com/payment/firsttimeuser.do

After putting in my phone number and the security code, I am getting:

Tarjeta de reembolso de T-Mobile

Please make a selection below to receive your payment

We were not able to validate the information provided. Please try again OR if you feel you've reached this message in error, please contact Customer Service.

Tried a few times with the same error.