I am supervising group of students who are using otree Hub's server deployment & Heroku.
2 students deleted their Heroku account last year when Heroku started to charge the accounts, but now they would like to run a new experiment. 
They were able to gain a new Heroku account, but they had used up the 2 public keys for oTree Hub and could not proceed. 
(The same problem as the post "How to recover Heroku public registration keys", but it is not my account but of my students.)
I am sorry for causing you this trouble, but would it be possible for you to renew the keys for them? 
What kind of information should I (or my students) provide to where in order to have this happen?

Thank you very much for your time.

My students were able to find ways to go around this problem. I would withdraw this question.