@Ashutosh Tripathi Thanks for your patience on this.
1.If someone is sending messages to that channel and receiving automatic replies via backend, where can I see these conversations?
We have metrics and logging for a WhatsApp channel as mentioned here. which gives details (like count or status) on message sent and received by a channel. ACS doesn't store those messages and also those are E2E encrypted so we can't see content of a message.
2.I believe ACS doesn't allows us to associate the number with WhatsApp if that number is getting used in ACS.
Above statement is not true, you can use ACS number to create WhatsApp Channel. Only requirement is that ACS Number should have capability of receiving SMS. You can find more detail in the below screenshot or refer to the perquisites called out in this doc .
3.Is there a way to use existing WhatsApp number with ACS?
Yes, we can but based on whether your phone number is present cloud API or in On-prem API as mentioned below
- If your Phone Number is associated to WhatsApp account in WhatsApp Cloud API then we can create channel for that WhatsApp account in ACS by disabling two-step verification for the phone number in WhatsApp portal (Refer => Migrate Numbers via Embedded Signup - WhatsApp Business Management API (facebook.com)) and then Create the channel in ACS.
- If a Phone Number is associate to WhatsApp account in On-Prem API then we need to allowlist the customer to migrate phone number to create WhatsApp channel in ACS. This process is done after customer complete steps mentioned in here => Migrate from On-Prem to Cloud - Cloud API (facebook.com).
4.it is not possible to use a channel for both automated and manual conversations or something else? --> Could you please more information to understand better.