Membership 2 Pro MailChimp Sync issue moving users from active to expired then back to active again

We are having many issues with the syncing of the Membership 2 Pro active users to MailChimp active users mailing list and then moving them back to the expired list when subscription expires and then moving back to active list when they re-pay and are re-activated. Below are some problems we have found.

EXPIRED USERS NOT MOVING to EXPIRED MailChimp list:
Expired Users in Membership 2 Pro stay in active members MailChimp list.
They did not move to MailChimp expired members list when expired.

Re-Activation of old USERS:
When an expired user pays a yearly renewal fee to re-subscribe, they are activated on Membership 2 Pro (clock updated or if a visitor subscription bar selected)
But we are having variable results with user synching to MailChimp.
Cant see pattern as there are varied results.. Some working occasionally.

Can you please see if this synching can be resolved when users expire and the re-subscribe

Could one issue be they cannot be re-subscribed back to a list once they leave?
If this is the case can we de-activate the UNSUBSCRIBED LIST from all MailChimp lists?

I have read that if a user is unsubscribed from the MailChimp list they can't be re-subscribed to that list unless email confirmation from MailChimp is sent to them. Should the Membership 2 Pro MailChimp add-on be delete the user from the MailChimp list instead of flagging them as unsubscribed?

Hoping you can help, I can supply logins and reference to specific user problems if it helps.

Thank you,
Martin