Unless you have enabled auto-renewal while making the payment, your proxies will expire at the end of your subscription period.
If in case your card is being charged even after canceling your subscription, please submit a request to email@example.com so we could look into the issue.
For payments made via Fastspring: After the first payment is completed, you get a payment receipt under which you will find a link to manage the subscription. Use the same link to cancel the subscription
In case, you are unable to find the receipt, send an email to firstname.lastname@example.org from your registred email address to manually cancel the subscription
For Credit Renewals: In case you use credits from your Limeproxies account for renewing your products, and you wish to cancel the renewal for a particular product, then please change the Auto Subscription option to disable on your Limeproxies Panel.