As a free user of Switch you will receive 25 free credits. Credits are deducted whenever you send a secure message to another free user and that user then opens the message.
If you have received an email saying you have run out of credits, you will no longer be able to use the Switch service to send securely to other free users and will need to purchase a subscription to continue to do so.
You can do this by clicking the ‘Purchase Switch’ button from the Switch Administration Panel.
NOTE: As a free user it is always free to correspond and initiate communication with a paid Switch user.