BalanceDao bd = new BalanceDao( con );
Contract contract = cm.getContractById( cid );
Сalendar date = Calendar.getInstance();
date = TimeUtils.getStartMonth( date );
ContractBalance contractBalance = bd.getContractBalance( contract.getId(), date.get( Calendar.MONTH ), date.get( Calendar.YEAR ) );
BigDecimal bb = bd.getBalance( contract.getId(), date.get( Calendar.MONTH ), date.get( Calendar.YEAR ) );
BigDecimal saldo = contractBalance.toBalance();
sb.append( "contractBalance:" + bb + ";" + contractBalance.getAccounts() + ";" + contractBalance.getCharges() + ";" + contractBalance.getPayments() + ";" + contractBalance.getReserve() + "\n");

contractBalance:0;0;0;0;0

import ru.bitel.bgbilling.kernel.container.managed.ServerContext;
import ru.bitel.bgbilling.kernel.contract.balance.common.BalanceService;
import ru.bitel.bgbilling.kernel.script.server.dev.GlobalScriptBase;
import ru.bitel.bgbilling.server.util.Setup;
import ru.bitel.common.sql.ConnectionSet;

import java.sql.Connection;
import java.util.Calendar;


public class TestGit
        extends GlobalScriptBase {
    @Override
    public void execute(Setup setup, ConnectionSet connectionSet)
            throws Exception {
        int contractId = 315753;

        Connection con = connectionSet.getConnection();
        ServerContext serverContext = ServerContext.get();
        BalanceService balanceService = serverContext.getService(BalanceService.class, 0);
        Calendar cal = Calendar.getInstance();

        print(balanceService.contractBalanceGet(contractId, cal.get(Calendar.YEAR), cal.get(Calendar.MONTH)).getPayments());
        print(balanceService.contractBalanceGet(contractId, cal.get(Calendar.YEAR), cal.get(Calendar.MONTH) + 1).getPayments());
    }
}

0
123123.00

 public ContractBalance getContractBalance(int contractId, int yy, int mm) throws BGException {