The expiry date of your plan is visible in your panel in several places. Here is how to find it:
Login to your SuperReceptionist account
Go to 'Account' section and click on 'Payments'
The expiry date will be visible under 'Plan Validity' on this page.
You can also visit the ‘Settings’ section on the panel to see your plan's expiry date under 'Call Flow' and 'SMS Flow'