Is the username registered for you on your PinToMind-account an old e-mail which is no longer in use?
If you remember your password:
Log in with your username and password, and go to "Menu" -> "Me" and update your e-mail-address there.
If you do not remember your password:
See if a registered administrator on the account can log in and send you a user-invitation to an e-mail you are using now. This can be done here under "Menu" -> "Users" in app.pintomind.com. The old user can just be deleted.
If you all have the same problem, or you were the only registered administrator, contact us at support@pintomind.com and we will be happy to help you take care of this!