<issue_start><issue_comment>Title: [It-11] Fix null balance issue
username_0: **Environment:** SIT
**Application:** swe.573.project
**Module:** BalanceService

**Affected User:** username_0
**Affected Customer:**

**Sample Information:**
SEVERE: Unexpected error occurred in scheduled task.
java.lang.NullPointerException
	at com.wolower.ui.service.BalanceService.updateBalance(BalanceService.java:30)
	at com.wolower.ui.service.payment.MasterpassPaymentScheduler.payment(MasterpassPaymentScheduler.java:75)
	at sun.reflect.GeneratedMethodAccessor107.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:483)
	at org.springframework.scheduling.support.ScheduledMethodRunnable.run(ScheduledMethodRunnable.java:65)
	at org.springframework.scheduling.support.DelegatingErrorHandlingRunnable.run(DelegatingErrorHandlingRunnable.java:54)
	at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
	at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308)
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180)
	at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at java.lang.Thread.run(Thread.java:745)

**Scenario it occurred:**
When saving new balance...<issue_closed>