How can my upload space be almost full when I have my jotform account connected to my google drive as the storage?

I have 3-4 different forms.

https://form.jotform.com/43455400524144

https://form.jotform.com/51788205231150

https://form.jotform.com/52577682411156 

Please be noted that the submissions received will be stored in your account and then sent to the integrated cloud storages like Google Drive/DropBox, etc. The integrated cloud storage can help you as a backup storage only for your submissions. 

In order to clear the storage space in your JotForm account, you'll need to delete the submissions that occupy with the attachments. Please make sure that you backup all your submissions including attachments since the submissions once deleted they cannot be retrieved in anyway. 

Hope this information helps! 

@Kiran: thank you Kiran.  This is helpful. When you say 'delete them' where do I delete them from? My google drive?  I can't seem to find any storage area on Jotform from which to delete them.

You may delete the submissions of your JotForm from the form submissions view. If you want to delete each submission one by one, you may click on Delete icon on the selected submission or X mark from the list view.

If you want to delete multiple submissions, you may select the required submissions to be deleted by holding the Ctrl key on the keyboard.

Hope this information helps!