Included in the
Send SMS action, there's an option called
Request delivery report, which when enabled, will return a delivery message back to the sender when it is received by the receiver. In order to detect this, when that report is activated, you can choose
Synchronous with timeout, that will keep your flow stopped in that action until the delivery report arrives or the specified timeout runs out. When this option is enabled, there's a variable
sms_delivery_report_status that gets created, so you can put an
Expression condition after the action and check whether the message was delivered or not. As the help of AM suggests, values of that variable between 0 to 31 mean a successful delivery, and otherwise pending or error. So if you determine after that condition, that the SMS wasn't delivered, you can loop back to the Send SMS action, and it will keep running until the receiver gets the message. For the timeout, I think you're good with 5-10m.
Also, you can limit the SMS attempts within the action, and so when surpassing that limit, it will throw an exception which you can use to get notified with a notification, for example.
I attach a flow that may do what you need.
http://automagic4android.com/flow.php?i ... 89bd6bea5d