Hello,
I don’t know whether it is proper to share my experiences here. Honestly, about two weekends ago, I did have encountered the similar Seagate hard drive document loss troubles caused by accidental format. All my work documents got cleaned. In order to rescue them back, I did also searched and tried many data recovery tools found over the internet.
And, some free data recovery tools really gave me some success, like:
Recuva [http://www.piriform.com/recuva|http://www.piriform.com/recuva] - free and fast
iCare Data Recovery Free [https://www.icare-recovery.com/|https://www.icare-recovery.com/] - 100% freeware and useful to take most of my lost files back
PhotoRec - free, but, the interface is difficult to operate.
PC Inspect Recovery – free and useful
Overall, if you are also stuck in such hard drive data loss issues, also go search for data recovery software to take chances.
Hope my answer also can help anyone over there.