Balance and Credit Limit
In addition to Tariff, each Customer or Account, except Root Customer, has those two basic rating/billing parameters associated with it – Balance and Credit Limit. Negative Balance represents amount of money Account or Customer is due to its owner, while positive one represents amount already deposited with the owner. Therefore, with each successful call the Balance goes down by the price of the call. Credit Limit set the maximum negative value the Balance can reach. After Balance has reached Credit Limit an Account or Customer will be blocked and not allowed to make any more calls.
The Balance can be increased via online payment, top-up voucher or by manual maintenance performed by the upper level Customer.