Just wanted to share my experience in recovering folder from internal memory of Hercules SGH-T989D.
I backed up WhatsApp folder to my computer however, it did not copy and I did not bother checking [my mistake]. I kept flashing nightly and formatted it 5 to 6 times.
Once I was done flashing the new ROM I noticed that WhatsApp folder was empty and wanted to recover it. I tried Undelete app but that did not return anything I tried DiskDigger returned pictures which I didn't need as Google Photo+ already backed it up for me. ( You guys should set up auto backup as well very good feature )
So I searched online and found ASoftTech Android Internal Memory Recovery post which was awesome. However, it lacked couple of things which made it difficult for me. It was mostly missing how to configure ADB.
I have listed the procedure which I followed and recovered my files I needed. I hope it helps someone else.
I am providing link to PDF to dropbox. I could not attach it as it was exceeding the attachment size limit. Hopefully someone can make a mirror to this file.
How to recover files from formatted internal memory on android 4.4+