Is it possible to transfer mail from nic.ru to Yandex.PDD while keeping letters and mailboxes?

Question

Yandex

Is it possible to transfer e-mail from the nic.ru service to the Yandex.Direct service while keeping mailboxes and letters.
Now clients receive mail on imap.
I understand that boxes \ passwords will most likely need to be created by hand, there are no problems with this, there are few boxes.
But what about letters?
PS nic.ru is not satisfied with his work, then the boxes are not available, then they are full, then something else.

Answer 1

Wouldn't advise.
Here, right now, several employees have a hard buggy mail, thunderbird reports various errors and does not load mail, and this happens with enviable regularity.
True, everything works through the web interface.

Answer 2

In biz.mail.ru it is possible to import users as a list + mail transfer:
https://help.mail.ru/biz/sys_admin/fromfile