An SMS in iSend goes through three phases: "Sent", when the mobile network has accepted it, "Delivered", when it has reached the recipient's device, and a final failure status ("Not delivered", "Expired", "Failed" or "Rejected"), when the network could not deliver it. For every message that ends in a failure status, iSend automatically refunds the credits to your balance.
The route of an SMS to the device
When you press send, iSend hands the message to the connectivity provider, the provider hands it to the recipient's mobile network, and the network hands it to the device. The device confirms to the network that it received it, and that confirmation, the delivery report, travels back to iSend. The status you see in the platform's Reports changes as soon as each such update arrives. This usually happens within a few seconds, but when the device is switched off it can take hours.
What each status means
| Status | What it means | Final? | Credits |
|---|---|---|---|
| Pending | The message is waiting in the iSend queue and has not yet been handed to the network. | No | Charged |
| Sent | The mobile network has accepted the message and is trying to deliver it. It does not mean the recipient received it. | No | Charged |
| Delivered | The recipient's device confirmed that it received the message. | Yes | Charged |
| Not delivered | The network tried but did not find the device available within the message's validity period. | Yes | Refunded |
| Expired | The message's validity period on the network ran out without the device appearing. | Yes | Refunded |
| Failed | The number does not exist, is not active, or the network returned a delivery error. | Yes | Refunded |
| Rejected | The network or the provider refused the message, for example because the number is barred or has an invalid format. | Yes | Refunded |
The "Delivered" status means the message reached the device, not that the recipient read it. SMS has no read receipt. The "Seen" indicator appears only for Viber messages.
The most common causes of failure
- Wrong or inactive number. This is the most frequent cause in lists that have not been cleaned for a while: a typo, a number that changed hands, a landline instead of a mobile. The number shows as "Failed" or "Rejected".
- Device switched off or without signal. The network holds the message and retries. If the device does not appear within the validity period, the message ends up "Expired" or "Not delivered".
- Incoming call barring or a porting problem. Numbers barred by their carrier or with a pending transfer to another network return "Rejected".
- Recipient who opted out. Anyone who replied STOP or is on your account's blocklist is not included in the send at all, so that you are not charged and do not violate their consent.
- Full memory or very old device. Rare, but real: the device rejects the message and the network reports it as "Not delivered".
What to do when you see failures
- Check the format of the numbers. A Greek mobile number has ten digits and starts with 69. Numbers starting with 2 are landlines and do not receive SMS.
- After each campaign, filter the "Failed" and "Rejected" messages in Reports and remove those numbers from the list. These numbers will not be delivered next time either.
- Wait before judging the "Sent" ones. A device that is switched off at night receives the message in the morning and the status changes to "Delivered".
- If a status stays "Sent" for more than one day, send us the number and the time of sending and we check it with the provider.
- A test message to your own mobile before the campaign shows whether the message or the numbers are at fault.
When credits are refunded
As soon as a final failure report ("Not delivered", "Expired", "Failed" or "Rejected") reaches iSend, the credits of that message, all of its parts, are automatically credited back to your balance. The transaction appears in the credit history marked as a refund. You do not need to request anything.
A message reported as "Delivered" is never refunded, even if a conflicting update arrives later from the network. A high failure rate in a single send triggers an automatic check of the list by the platform, to protect your Sender ID and the network from sends to purchased or outdated lists.
Where you see the statuses
In the platform's Reports menu, every message has its own row with recipient, time, status and credits. The filter buttons at the top show, with one click, only the "Delivered", "Not delivered", "Failed", "Expired" or "Rejected" messages. For each campaign the overall delivery rate is also shown on the reports and statistics page.
Frequently asked questions
Does "Sent" mean the recipient received the message?
No. It means the mobile network has accepted it and is trying to deliver it. Receipt by the device is confirmed only by the "Delivered" status. If the device is switched off, the message stays "Sent" until it is switched on or until it expires.
Why does a message show "Delivered" while the customer says they did not see it?
The "Delivered" status comes from the device, which confirmed receipt to the network. The most common explanations are that the message ended up in the spam folder of the messaging app, that it was deleted, or that the number is used on another device. A second test message to the same number usually clears up the picture.
Am I charged for an SMS that was not delivered?
No. Every message that ends in a final failure status automatically refunds its credits to your balance. Only messages that the network accepted and delivered, or that are still in progress, are charged.