这是我参考的接口文档

https://developers.weixin.qq.com/miniprogram/dev/platform-capabilities/business-capabilities/ministore/wxafunds/API/order/refunds_order.html

这是我的请求json
{"openid":"o0LpF5O1Q5K8_GBQYDtFIpJMbJ9I","mchid":"1628666891","trade_no":"400717513491259257-mini-mini","transaction_id":"4334901115202209261514916233","refund_no":"554240220926142617","refund_amount":1810,"total_amount":1810}

这是我的url

https://api.weixin.qq.com/shop/pay/refundorder?access_token=61_a0J1DmDvIPm_CbGrECq6utqO822sORG1wM1e6cpBiOUNnj88KzsW88yhYICeyQGLP1cleMBVhA5OcGlx4Mtrk6_nDZEwwlLqM0a2QQGzW4x5dwI3tkBU7QjIbeO-t06xZSFfSuQ63DYYR0GCVHJgAFARDF

这是报错

{"errcode":9720001,"errmsg":"参数错误 combine_trade_no: expecting combine_trade_no.size >= 6, actually 0 rid: 633259cc-57a618b2-6f2420c3"}