It depends – if our system detects a problem with the number, it won't send your message and you won't be charged. For example, if there's a validation error when you try to send to a country you are not authorized to send to, if there is a billing issue, or if there's an incorrect number prefix.

However, if the message leaves our system, you will pay to send it, even if it isn't successfully delivered – for example, if the number has been delisted or ported.