disk become empty after delete a large file

I have a 2T mobile disk with the format of NTFS. I store 1T files on it, including a large file with the size of 260G.

After I delete the large file, all the file was gone. I remount the disk again and again , it remains the same. I am using os x lion.

Here is the result of df -h

Filesystem      Size   Used  Avail Capacity   iused      ifree %iused  Mounted on
/dev/disk0s2   931Gi  486Gi  445Gi    53% 127448441  116532301   52%   /
devfs          332Ki  332Ki    0Bi   100%      1149          0  100%   /dev
map -hosts       0Bi    0Bi    0Bi   100%         0          0  100%   /net
map auto_home    0Bi    0Bi    0Bi   100%         0          0  100%   /home
/dev/disk1s1   1.8Ti  874Gi  989Gi    47%     57185 1036883723    0%   /Volumes/Seagate Backup Plus Drive

Notice the last line, 874Gi Used but 0% iused. What I can concluded is the files are still on the disk but I can't see them. Maybe some inode is broken.

So how can I save my file on the disk. Any method to copy the file to another disk or repair the mobile disk?