A bug in the hosting or how to make money out of thin air

Greetings

While foreign companies pay for bugs, Russian companies say thank you or don’t say anything at all, silently correcting a mistake found by another person.
I want to share what happened during the August day.
And now more to the point ...
In one ordinary day, I discovered an unpleasant for them (and even very pleasant for us) bug on one well-known hosting.
With this bug you can achieve this result (even more, we are not limited by anything, only conscience) ...

We are interested in the balance that is below, highlighted in a black square, because it can be displayed on webmoney, and more recently there was zero.
The fact is that this hoster has an affiliate program, according to which percentages are transferred to the client, from the people listed by him.
With this money you can:

• pay for hosting
• withdraw money to webmoney,
• transfer to partners

in all previously mentioned transactions, money is deducted from the bonus balance.
So with the first, they have a problem. Apparently, programmers didn’t consider it necessary to check the entered data, so we don’t have anything to prevent entering a negative amount, and as you remember from a higher mathematics course, a minus gives you a minus plus, so if you pay -20 rubles -> the balance will add +20 rubles, and now in numbers:
It was 1287.00 rub.
pay at -20rub.
we get
1287 - (-20) = 1307 rub.
not bad, huh?


although the payment has already been made, as you can see the amount has increased by 20 rubles.

You can only print on webmoney.
Remember that there seems to be such a trifle in the code (and it was just worth writing something like this)

if ( isset ( $ _POST [ 'money input field for payment' ] ) && ( $ _POST [ 'money input field for payment' ] > = 0 ) ) {
// you can conduct a transaction
}
else {
echo ( "ah ah ah" ) ;
}

can be expensive ...
Of course, I, as a good person, notified those. hosting support, however the reaction was not immediate, thanks I heard after 4 hours:
')
"Hello. Thanks for pointing out the error. Your request has been sent to programmers. We will try to fix the problem as soon as possible. ”
However, the problem was fixed somewhere in a month.