What if the leader sends an email to criticize?

Personally, I think it's a little inappropriate for you to reply to the email, so it's better to reply by SMS. The contents of the reply can be considered as follows:

I apologize for my incomplete knowledge and how to improve myself in the next step, and thank the leaders for their cultivation and concern. I am very moved by this warning. I will study hard, work hard and be competent with practical actions.