To get a complete idea of the features of your current plan, you can check this out.
To remove the Rocketium logo, go to Logo in the left panel and select 'Remove Logo'
If this does not work, please check your video count from the Dashboard. It is there in the top right corner of your screen. Click on it. If the count is 0 and you are within the renewal date, all your published videos will come with the Rocketium logo and watermark.
You can either buy extra credits or you can save your video as a draft (click here to know how) and publish them once your cycle is renewed.