Notification System: Retries and Duplicates

At 12:41:05 the card system held a payment of 1,180 dollars and created a fraud check for account ACC-5521. An SMS consumer took the record and called the provider. Ten seconds later the call timed out, so the consumer released the record, and a second consumer sent it again. This time the provider answered at once.

The customer received the same text twice, 12 seconds apart, and called the bank to ask whether two payments had been held. The provider's report later showed that the first call had succeeded: the reply had been lost, not the message. Nothing in the design was broken