TestFlight problem

I was using an vpn product through TestFlight. I’ve purchased one years’ membership and used just a month which appeared suddenly quit problem and can’t login any more yesterday. Then I uninstalled the app and prepared to re-install it but be announced removed from the test programme that my Apple ID is not active😭 What can I do now and I think I need a redeem code for the test.

Thank you for the help

TestFlight problem
 
 
Q