Happy to help! Yes, if they have an IQ Panel 2 or IQ Panel 4 at the location, as long as the prior Alarm.com account linked to it has been cancelled you would be able to reuse that panel with Surety.
I am linking a guide to using an existing IQ Panel at the bottom. If the Alarm.com account was not cancelled and the prior owners can’t assist with getting it cancelled, you could reuse all the existing sensors and any Z-wave devices with a new panel.
Have you checked the IMEI? You can do so here to see if the panel is still registered.