When a subscription is cancelled, it will expire at the time of renewal, which could be next month or year depending on your plan. At this point, you will not be charged again. This means that you can still enjoy all the benefits from a paid subscription until then.
If you're unsure of when your subscription expires, please check "My Subscription" which you find under the cog wheel in the upper right corner of your profile page.
If you feel like you've been charged although you shouldn't because you already cancelled your subscription, please contact us at support [at] soundtrap.com.