curl --request GET \
  --url https://api.heyy.io/api/v2.0/contacts/{contactId} \
  --header 'Authorization: Bearer <token>'

{
  "data": {
    "id": "<string>",
    "createdAt": "<string>",
    "updatedAt": "<string>",
    "firstName": "<string>",
    "lastName": "<string>",
    "phoneNumber": "<string>",
    "email": "<string>",
    "labels": [
      "<string>"
    ],
    "attributes": [
      {
        "name": "<string>",
        "value": "<string>"
      }
    ]
  }
}