A million years ago, our invented such a service - SMS notification of disbursements from the subscriber's account. No one for five years!! None of the millions of subscribers used this service. Yesterday was suffering.
And some idiot-scriptologist, this service did not depend on the bound-abonnent, which is written off once a month, but on random copies for each operation. and
I forgot to fix in the payment field.
At the test stage, everything was messed up - there was no bonding. Here is the first!) For five years, the customer has signed up for this service. I sent a SMS and received a notification - "50 copies". And then he wrote off three pennies for receiving this notification.
And they sent a new notification of "3 copies" for which they wrote off 5 copies and sent a notification. In general, the pop had a dog.. endless cycle, 1-5 copies per iteration, speed ~ 1 sms/sec. For domestic services, a default rate is not established.
In short, until we understood, the guy for 10 pieces in minus went away, his phone died from overheating, and we had all the sots from the area pulled off to this hut, where the subscriber lived!