It depends If our system detects a problem with the number, it will not send your message and you will not be charged. For example, if there is a validation error, if you try to send to a country you are not authorized to send to, if there is a billing issue or if there is an incorrect number prefix.
However, if the message leaves our system, you will pay to send it, even if it is not successfully delivered for example, if the number has been delisted or ported.
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