<xml>

    <nonce_str>88630f9a9e9c4b33b064d0afe42e03c3</nonce_str>

    <out_trade_no>33513711643181625117</out_trade_no>

    <out_refund_no>33513711643181625117</out_refund_no>

    <appid>wxfc5c98bc94248dd4</appid>

    <refund_fee>100</refund_fee>

    <total_fee>100</total_fee>

    <sign>3CEB59A0D616DC44D7BA6EB211A41350</sign>

    <mch_id>1800008281</mch_id>

    <sub_mch_id>1619744204</sub_mch_id>

</xml>

https://api.mch.weixin.qq.com/secapi/pay/refund 服务商模式调用的这个退款接口，一直报签名错误