Hey Jhay,
Unfortunately the factory reset will not do the trick here, as Philip mentioned underneath.
I'm afraid there's not going to be much you can do if the ISP didn't unclaim the units before giving them away, as these now count as second hand and will be subject to the caveats we documented here:
https://documentation.meraki.com/General_Administration/Inventory_and_Devices/Cisco_Meraki_Devices_p...
Warranty is also non-transferable.
Hope this helps to at least provide some clarity!
Giac
Please keep in mind that what I post here is my personal knowledge and opinion. Don't take anything I say for the Holy Grail, but try and see!
Appreciate who helps and be respectful of every opinion and every solution offered.
Share the love, especially the Meraki one!