I will definitely help you to get the Temporary Port-Out PIN. You can generate it using the T-Mobile Application under the Primary Account Holder Line and it will be valid within 7 days once you generate a code.  
 
Just Make sure the T-Mobile app is on the latest version before attempting these steps. 
 
Download and log in to the T-Mobile app . 
Select Account. 
Select Profile Settings. 
Select Line Settings. 
Select Request a transfer PIN. 
Follow the directions on the screen