Hello
I would like to use nibblebilling for fraud prevention on international and premium numbers ( national or emergency calls should never be blocked and should still working even if the billing database is unavailable  )

Unfortunately that never hangup my calls using standard dial plan

nibblebill.conf.xml

<configuration name="nibblebill.conf" description="Nibble Billing">
  <settings>
    <!-- See http://wiki.freeswitch.org/wiki/Mod_nibblebill for help with these options -->

    <!-- Information for connecting to your database -->
    <param name="db_dsn" value="pgsql://hostaddr=127.0.0.1 dbname=xxxx user=xxxx password=xxxx"/>

    <!-- The database table where your CASH column is located -->
    <param name="db_table" value="accounts"/>

    <!-- The column name where we store the value of the account -->
    <param name="db_column_cash" value="cash"/>

    <!-- The column name for the unique ID identifying the account -->
    <param name="db_column_account" value="id"/>

    <!-- Default heartbeat interval. Set to 'off' for no heartbeat (i.e. bill only at end of call) -->
    <param name="global_heartbeat" value="20"/>

    <!-- By default, warn a caller when their balance is at $5.00. You can set this to a negative number. -->
    <param name="lowbal_amt" value="-100"/> <!-- i don't need this -->
    <param name="lowbal_action" value="play ding"/>

    <!-- By default, terminate a caller when their balance hits $0.00. You can set this to a negative number. -->
    <param name="nobal_amt" value="0"/>
    <param name="nobal_action" value="hangup"/>

    <!-- If a call goes beyond a certain dollar amount, flag or terminate it -->
    <param name="percall_max_amt" value="10"/>
    <param name="percall_action" value="hangup"/>

  </settings>
</configuration>

outbound route

<extension name="international" >
   <condition field="destination_number" expression="^00(\d{6,20})$" >
       <action application="nibblebill" data="flush"/>
        <action application="set" data="nibble_account=${accountcode}"/>
        <action application="set" data="nibble_rate=0.1"/>
       <action application="bridge" data="sofia/gateway/gw_idt/$1" />
   </condition>
</extension>


My balance
My balance is already negative

 select * from accounts ;
                id                |   cash   
----------------------------------+-----------
 company.voip.mydomain.com | -0.789471

A sample call
My balance already negative, the call will be billed but never blocked

Dialplan: sofia/internal/5003@company.voip.domain.com Action nibblebill(flush)
Dialplan: sofia/internal/5003@company.voip.domain.com Action set(nibble_account=${accountcode})
Dialplan: sofia/internal/5003@company.voip.domain.com Action set(nibble_rate=0.1)
EXECUTE sofia/internal/5003@company.voip.domain.com nibblebill(flush)
EXECUTE sofia/internal/5003@company.voip.domain.com set(nibble_account=company.voip.domain.com)
2016-04-10 12:10:04.049418 [DEBUG] mod_dptools.c:1477 sofia/internal/5003@company.voip.domain.com SET [nibble_account]=[company.voip.domain.com]
EXECUTE sofia/internal/5003@company.voip.domain.com set(nibble_rate=0.1)
2016-04-10 12:10:04.049418 [DEBUG] mod_dptools.c:1477 sofia/internal/5003@company.voip.domain.com SET [nibble_rate]=[0.1]
2016-04-10 12:10:52.132458 [DEBUG] mod_nibblebill.c:488 Attempting to bill at $0.1 per minute to account company.voip.domain.com
2016-04-10 12:10:52.132458 [INFO] mod_nibblebill.c:540 Beginning new billing on 644488fc-ff04-11e5-9a27-fd2791153af9
2016-04-10 12:10:52.132458 [DEBUG] mod_nibblebill.c:546 42 seconds passed since last bill time of 2016-04-10 12:10:09
2016-04-10 12:10:52.132458 [DEBUG] mod_nibblebill.c:563 Billing $0.071033 to company.voip.domain.com (Call: / 0.000000 so far)
2016-04-10 12:10:52.132458 [DEBUG] mod_nibblebill.c:393 Doing update query
2016-04-10 12:10:52.172440 [DEBUG] mod_nibblebill.c:420 Doing lookup query
[SELECT cash AS nibble_balance FROM accounts WHERE id='company.voip.domain.com']
2016-04-10 12:10:52.172440 [DEBUG] mod_nibblebill.c:428 Retrieved current balance for account company.voip.domain.com (balance = -0.860504)


Using b-leg only
Alternatively i tried an alternative dialplan ( Even if i don't relay understand what is the meaning of b-leg billing  )

<action application="bridge" data="{enable_heartbeat_events=5,nibble_rate=0.1,nibble_account=${accountcode},originate_timeout=90}sofia/gateway/gw_idt/33$1" />

The result is better because the pending call is hanged up when the balance reach 0.

2016-04-10 12:39:59.012462 [CRIT] mod_nibblebill.c:607 Balance of -0.003237 fell below allowed amount of 0.000000! (Account company.voip.domain.com)

But if i make a new call ( when my balance is negative )  , the caller party is immediately hanged but this did not cancel immediately the bridge:  The called party ring and can stay bridged for 61 seconds after answer.