You might want to look Tools · Esri/ago-admin-wiki Wiki · GitHub for some tools that might help you with moving items between AGOL sites, but you will probably need to get help from someone with admin rights in the old work location. If it's in their Enterprise account and not shared, and your account was disabled, I doubt you can access it. If they deleted the items, they may not be able to be recovered. This is based on posts I've seen, I am not an authoritative voice for this.
You may also need to contact tech support. I'm not sure if they can help without user account permissions either, but you never know. However, my guess, re: leaving the group and deleting the organization is they may be able to help there (you will need to delete/move all items the user owns to delete a user, but an AGOL site ??. If you can add a user to the site, you may just be able to fire up a dummy account, transfer all to that new account, then delete your account.