There were a lot of times when I regretted deleting files from my USB stick as later on they proved to still be useful. A program that turns out to be of good use in this kind of situations is iCare Card Recovery Pro.
A good aspect about this application was that it didn't come with an overwhelming interface and displayed just a few necessary buttons, making the program accessible for any type of user, beginner and professional. But, if you have difficulties in handling the program, the only help you can get is from the homepage of the developer as the program lacks a help manual.
What I didn't like at all about this application was its slow scan and not having the ability to pause and resume the scanning process. At least the results were complete and I was able to recover all the files I needed.
No matter the cause of data loss from your USB stick, whether it was an accidental format or just a memory card error, iCare Card Recovery Pro will safely restore the lost documents at a reasonable cost.