Login to iPlum web portal https://my.iplum.com.
Click “Billing” in left menu. Add your payment method here. If your existing payment method is failing, delete it and redo the new payment method. If you have set up multiple payment sources, select the one you want to use as “Default”.
Toggle green “Enable credits auto-load”, set the threshold and save it.
This will allow the system to load one-time 2,000 usage credits for $19.99 when the plan credits gets exhausted for any iPlum line, and those same credits will be subsequently used as “overlay” for that line for 1 year whenever you have used your allocated monthly usage plan credits.