curl --request POST \
  --url https://api.multchats.com/v2/integration/validate-whatsapp-phone-number \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '
{
  "integrationId": "<string>",
  "phoneNumber": "<string>"
}
'

{
  "success": true,
  "response": {
    "exists": true,
    "jid": "<string>"
  }
}