A ticket is generated whenever a customer messages you. However, DelightChat counts it as a billable ticket only when a human replies to a ticket.
Example: say you receive WhatsApp messages from 100 unique customers. And you reply to 90 of them. Those 90 are counted in your monthly plan.
Example 2: say you receive 50 emails, you reply to 40 of them. Those 40 are counted towards your monthly tickets quota.
Within the same ticket, you can send & receive as many messages as you need. It is counted as 1 ticket.