Hello Leo,

I still have money for memberships & website shows paid membership is active.
After cancellation , subscription will get expired on expiratio date set by initial payment's, only further recurring payments will not charged.
After expiration the only way to re-activate that subscription is renewal.

Yes, you need to contact paypal team , that is it possible to revert cancel option from paypal account.
Because cancellation done at paypal end itself.

Update me if you have any query.