An example of a defect in the billing of a Corbin company (Beeline)

One forgotten symbol when writing a billing for such a large one as Corbina can bring a lot of negative to subscribers of the company, or lead to loss of a client.

Here is a screenshot of your personal account, which clearly demonstrates the identified error.



I will explain in more detail the essence of the error: when debiting funds, a check is made to see if the user's balance is greater than the amount required to be debited , but it is not checked whether the balance is equal to the amount debited.
For subscribers who encounter such a problem, the support service politely offers to pay 1 ruble to make it work.

Do not forget to consider all the nuances regarding any data checks when developing user interfaces.