How to show alert message when backend workflow fails?

Hi All.

Does anyone know how I can show an alert on the page when a backend worflow fails?

Eg. Im running scheduled workflow on a list, the list is a list of customers that im sending sms messages to. I want to be able to show to my user if they dont have enough sms credits. So it may be sending to some customers but then if they run out midway through the list sending, the alert will show.

I can do this no problem on the frontend with conditionals, but i dont get the option to show an alert on a backend workflow.