How long are back-ups saved on your servers?

Can you tell me how long uploaded files, that I delete from my account, are still being stored on your servers (for back-up purposes)? I want my (deleted) files (which are privacy-sensitive) to be fully deleted a.s.a.p., so that their are no tracks left! Do you have a privacy-paper, in which these issues are clarified?

Files and submission data are removed immediately after they are deleted.  For better or for worse, we do not keep backups of deleted form data. 

Here is our privacy policy:

https://www.jotform.com/help/9-Privacy-Policy