If user is deleted, you can create user with same email again. I did this once in the past, haven't tested later on. You may proceed creating a new account, deleting it and recreating it to be sure.
If you are unsure of entire procedure, id rather not end up looking a bad guy that screwed you up.
Advices i gave you are something that i would do if i ended up with that problem. And you can either try them, or wait for official update/information that will fix your problem.
What I would do is:
Cancel Sharing
Delete devices from hik connect
Delete Hik connect account
Create account
Add devices back on
Share devices to users that had it before
As i said in previous posts, this problem does not occur on my side, and all this is improvisation which i would take ,and cant give you any 100% guarantee that everything will work 100% as it was. Afterall I'm not developing Hik connect, i am user.