I have deleted half of my submissions and still out of space ??

Your account seem to have reached the submissions limit, this is why even when you have downloaded some of them, you can still see you are on the overlimit status. 

I would recommend you to complete the tasks under the get more section on my account page, you will receive submissions for each completed task: https://www.jotform.com/myaccount/getMore 

Otherwise, if you would need to have more submissions, you will need to upgrade your account. https://www.jotform.com/help/331-How-to-Upgrade-My-Account 

I hope this helps.