Previous Owner Account Deactivation

We purchased a new house & want to use the system that was left behind, including the doorbell camera which the old owner never removed from the account. I have attempted to reach out to the previous home owners to deactivate their account but they have been unresponsive. I spoke live with a SimpliSafe representative this afternoon to explain the situation and they said my only option was to get the previous homeowners to call them directly to deactivate the account (which they won't do) or I would have to purchase a brand new device and register it. This is disappointing and I'm hoping there are other options so I don't have to purchase a new system.