curl --request GET \
  --url 'https://api.stateset.com/api/v1/ar/collection-activities' \
  --header 'Authorization: Bearer YOUR_API_KEY'

{
  "activities": [
    {
      "activity_type": "string",
      "contact_method": null,
      "contact_result": null,
      "created_at": "string",
      "customer_id": "string",
      "dunning_letter_type": null,
      "id": "string",
      "invoice_id": "string",
      "notes": null,
      "performed_by": null,
      "promise_to_pay_amount": null,
      "promise_to_pay_date": null
    }
  ],
  "total": 1
}