Hi eliteksolutions,
Thank you for your purchase.

This is not the case, that slot should be available after cancellation.

Can you please tell me which version of our plugin do you use? Is it 2.6?

Best regards.

Hello robin

Is this a group appointment, or a single-customer appointment? Are you cancelling the customer, or the entire appointment.

When you cancel an appointment, that time slot has to be open for another appointment. If this is not the case, please open a new private ticket, and provide us with the wp-admin credentials, so we can remote into your website, and check it.