I was still charged even though account canceled?

After a termination always comes the notice period. After the notice period, you will still receive the final invoice.

The notice period always lasts until the next billing period.

As an example:

You have terminated the contract on the 15th of the month. This means that your billing period lasts until the 15th of the next month.

Example:

You cancel on the 5th of month. Your cancellation period ends on the 15th of the month. Or you cancel on the 20th of the month, in which case the cancellation period lasts until the 15th of the next month.

After that, you will receive the final invoice.