Splashtop does not send out email reminders for subscription renewals as auto-renewal is enabled by default. Right after you subscribe, you will be able to see the subscription with auto-renewal enabled in the "Subscriptions" section in your management portal here: https://my.splashtop.com/account_info/#subscription_tab
If you do not want to be charged after the subscription cycle, you can turn off auto-renewal.
Turning off auto-renewal
Here is an example of what you might see when you login to your portal if you turned off auto-renewal and the subscription cycle is ending:
You will also see this reminder when your expiration date is approaching
If you would like to manage your Splashtop Business subscription, please see this article: