diff --git a/src/main/kotlin/com/android/trisolarisserver/controller/PayuQrPayments.kt b/src/main/kotlin/com/android/trisolarisserver/controller/PayuQrPayments.kt
index a016db4..fec4ca0 100644
--- a/src/main/kotlin/com/android/trisolarisserver/controller/PayuQrPayments.kt
+++ b/src/main/kotlin/com/android/trisolarisserver/controller/PayuQrPayments.kt
@@ -144,32 +144,32 @@ class PayuQrPayments(
         )
 
         val form = LinkedMultiValueMap<String, String>().apply {
-            add("key", settings.merchantKey)
-            add("txnid", txnid)
-            add("amount", amount)
-            add("productinfo", productInfo)
-            add("firstname", firstname)
-            add("email", email)
-            add("phone", phone)
-            add("surl", buildReturnUrl(propertyId, true))
-            add("furl", buildReturnUrl(propertyId, false))
-            add("pg", "DBQR")
-            add("bankcode", "UPIDBQR")
-            add("hash", hash)
-            add("udf1", udf1)
-            add("udf2", udf2)
-            add("udf3", udf3)  // always
-            add("udf4", udf4)  // always
-            add("udf5", udf5)  // always
-            add("txn_s2s_flow", "4")
+            set("key", settings.merchantKey)
+            set("txnid", txnid)
+            set("amount", amount)
+            set("productinfo", productInfo)
+            set("firstname", firstname)
+            set("email", email)
+            set("phone", phone)
+            set("surl", buildReturnUrl(propertyId, true))
+            set("furl", buildReturnUrl(propertyId, false))
+            set("pg", "DBQR")
+            set("bankcode", "UPIDBQR")
+            set("hash", hash)
+            set("udf1", udf1)
+            set("udf2", udf2)
+            set("udf3", udf3)  // always
+            set("udf4", udf4)  // always
+            set("udf5", udf5)  // always
+            set("txn_s2s_flow", "4")
             val clientIp = request.clientIp?.trim()?.ifBlank { null }
                 ?: extractClientIp(httpRequest)
                 ?: throw ResponseStatusException(HttpStatus.BAD_REQUEST, "clientIp required")
             val deviceInfo = request.deviceInfo?.trim()?.ifBlank { null }
                 ?: throw ResponseStatusException(HttpStatus.BAD_REQUEST, "deviceInfo required")
-            add("s2s_client_ip", clientIp)
-            add("s2s_device_info", deviceInfo)
-            add("expiry_time", expirySeconds.toString())
+            set("s2s_client_ip", clientIp)
+            set("s2s_device_info", deviceInfo)
+            set("expiry_time", expirySeconds.toString())
             request.address1?.trim()?.ifBlank { null }?.let { add("address1", it) }
             request.address2?.trim()?.ifBlank { null }?.let { add("address2", it) }
             request.city?.trim()?.ifBlank { null }?.let { add("city", it) }