微信小店ISV推送的消息格式：

{    
    "finder_shop_aftersale_status_update": "\n2000003430069354\nMERCHANT_PROCESSING\n3736396724586553600\n",
    "CreateTime": "1778834628",
    "Event": "channels_ec_aftersale_update",
    "ToUserName": "gh_1f7515a225b1",
    "FromUserName": "o3I9D2dame5vGcbjoNsF6LvKWMnw",
    "MsgType": "event"
}

商家自研的推送的消息格式：
{
     "ToUserName": "gh_09a08d72d1a6",
     "FromUserName": "oHkRE2TYh-9oy6azW7zk4AUMlPzg",
     "CreateTime": 1778835204,
     "MsgType": "event",
     "Event": "channels_ec_aftersale_update",
     "finder_shop_aftersale_status_update":
     {
         "after_sale_order_id": "2000003413203552",
         "status": "MERCHANT_PROCESSING",
         "order_id": "3736171021465426432"
     }
 }

文档中的格式：
https://mmbiz.qpic.cn/sz_mmbiz_png/nMl9ssowtibWoKFKOcbwvrrW0ibPmaVEpL0MqCDE9icWDpzXhFLWJVGWCc8qFLL2Wg0ZUXquhX7xRbNl0rVY5flA97JY7Enr9QPedphQrgEQbE/0?wx_fmt=png
https://developers.weixin.qq.com/doc/store/shop/notify/aftersale_callback/channels_ec_aftersale_update.html