Adobe Acrobat 2020 - This serial number is already in use

It seems we ran out of activations for our 21 licences for Adobe Acrobat 2020. We recently switched out alot of our old pcs and notebooks for new ones and did not deactivate or uninstall Adobe Acrobat 2020 before discarding them.

How can we get back our activations when we do not have access to the old hardware (the harddrives were shredded)?

Thank you!