After using it we realize that the APIs are really limited. I would like you to improve two points:
1. When trying to add a contact via WhatsApp number, if it already exists the system returns an error: "This WhatsApp ID already exists: XXXX". It would be appropriate if it also returned the subscriber ID, in this way you could make a subsequent call and update it.
2. It is not possible to search for a subscriber via WhatsApp ID but only via email or SMS.

Currently these steps make it difficult to have a flow where you want to import a subscriber and send an automatic message via WhatsApp because you cannot manage in any way the cases in which the subscriber is already present. If the system returned the subscriber ID when it is already present, everything could be managed better. Therefore, solutions are required for:
1. Being able to search if a subscriber is present and retrieve its ID via the WhatsApp number
2. Having the subscriber ID when trying to import it via WhatsApp number.