<?xml version="1.0" encoding="UTF-8" standalone="no"?>

<xml>

<amount>1</amount>

<nonce_str>3PG2J4ILTKCH16CQ2502SI8ZNMTM67VS</nonce_str>

<mchid>**********</mchid>

<openid>********</openid>

<partner_trade_no>16181975756472531120210412111935</partner_trade_no>

<mch_appid>wx9533e15**********</mch_appid>

<sign>1A08B6F7DE999753876946BA063812C2</sign>

<check_name>NO_CHECK</check_name>

<desc>余额退款</desc>

</xml>

参数应该没问题？是为什么