diff --git a/rc-service/rc-service-wallet/wallet-infrastructure/src/main/java/com/red/circle/wallet/infra/database/mongo/service/bank/impl/UserBankBalanceServiceImpl.java b/rc-service/rc-service-wallet/wallet-infrastructure/src/main/java/com/red/circle/wallet/infra/database/mongo/service/bank/impl/UserBankBalanceServiceImpl.java
index a56d2389..de048f1d 100644
--- a/rc-service/rc-service-wallet/wallet-infrastructure/src/main/java/com/red/circle/wallet/infra/database/mongo/service/bank/impl/UserBankBalanceServiceImpl.java
+++ b/rc-service/rc-service-wallet/wallet-infrastructure/src/main/java/com/red/circle/wallet/infra/database/mongo/service/bank/impl/UserBankBalanceServiceImpl.java
@@ -13,11 +13,12 @@ import com.red.circle.wallet.inner.model.dto.BankBalanceDTO;
 import com.red.circle.wallet.inner.model.dto.UserBankBalanceDTO;
 import java.util.Collection;
 import java.util.List;
-import java.util.Map;
-import java.util.Objects;
-import java.util.stream.Collectors;
-import lombok.RequiredArgsConstructor;
-import org.springframework.data.domain.Sort;
+import java.util.Map;
+import java.util.Objects;
+import java.util.stream.Collectors;
+import lombok.RequiredArgsConstructor;
+import org.bson.Document;
+import org.springframework.data.domain.Sort;
 import org.springframework.data.mongodb.core.FindAndModifyOptions;
 import org.springframework.data.mongodb.core.MongoTemplate;
 import org.springframework.data.mongodb.core.query.Criteria;
@@ -80,12 +81,23 @@ public class UserBankBalanceServiceImpl implements UserBankBalanceService {
   }
 
   @Override
-  public BankBalanceDTO getBalance(Long userId) {
-    return BankBalanceDTO.of(mongoPrimaryService.find(UserBankBalance.class,
-        Filters.eq("_id", userId),
-        documents -> CollectionUtils.isEmpty(documents) ? 0L
-            : documents.get(0).getLong("balance")));
-  }
+  public BankBalanceDTO getBalance(Long userId) {
+    return BankBalanceDTO.of(mongoPrimaryService.find(UserBankBalance.class,
+        Filters.eq("_id", userId),
+        documents -> CollectionUtils.isEmpty(documents) ? 0L
+            : getLongValue(documents.get(0), "balance")));
+  }
+
+  static Long getLongValue(Document document, String key) {
+    Object value = document.get(key);
+    if (Objects.isNull(value)) {
+      return 0L;
+    }
+    if (value instanceof Number) {
+      return ((Number) value).longValue();
+    }
+    return Long.valueOf(value.toString());
+  }
 
   @Override
   public Map<Long, BankBalanceDTO> mapBalance(Collection<Long> userIds) {
diff --git a/rc-service/rc-service-wallet/wallet-start/src/test/java/com/red/circle/wallet/infra/database/mongo/service/bank/impl/UserBankBalanceServiceImplTest.java b/rc-service/rc-service-wallet/wallet-start/src/test/java/com/red/circle/wallet/infra/database/mongo/service/bank/impl/UserBankBalanceServiceImplTest.java
new file mode 100644
index 00000000..a277c669
--- /dev/null
+++ b/rc-service/rc-service-wallet/wallet-start/src/test/java/com/red/circle/wallet/infra/database/mongo/service/bank/impl/UserBankBalanceServiceImplTest.java
@@ -0,0 +1,30 @@
+package com.red.circle.wallet.infra.database.mongo.service.bank.impl;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import org.bson.Document;
+import org.junit.jupiter.api.Test;
+
+class UserBankBalanceServiceImplTest {
+
+  @Test
+  void getLongValueAcceptsIntegerBalance() {
+    Document document = new Document("balance", 0);
+
+    assertEquals(0L, UserBankBalanceServiceImpl.getLongValue(document, "balance"));
+  }
+
+  @Test
+  void getLongValueAcceptsLongBalance() {
+    Document document = new Document("balance", 123L);
+
+    assertEquals(123L, UserBankBalanceServiceImpl.getLongValue(document, "balance"));
+  }
+
+  @Test
+  void getLongValueDefaultsMissingBalanceToZero() {
+    Document document = new Document();
+
+    assertEquals(0L, UserBankBalanceServiceImpl.getLongValue(document, "balance"));
+  }
+}