I have the same device. it is formatted as NTFS by default, and as much as I know, if you remove an NTFS formatted drive from the system without "safely remove", you will not face serious problems.
when you connect a storage device to your computer, the operating system (your windows) will provide an interface for the user to work with the file system on the device, this process is called "mounting". for example when you attach a storage device to your windows PC, windows creates a "drive" in your computer and assigns a drive letter (say H:) to access the file system on the drive. then the user can access files on the drive (through applications, like windows explorer or any file manager). after you're done with the device, you should "unmount" the device, which means the operating system will make sure no application is using the files on the drive. this is called "safely remove" on windows. if you do not do this, AND at the same time an application was accessing files on the drive, you could face corrupted files.
however, NTFS (like many other journaled file systems), somehow protects the user in most of these cases. this means if somehow the drive could bot be "unmounted" properly, your files are most likely safe to corruption, but you might face some data loss.
after all these, I'm saying I don't think that the act of removing the device without pressing the "safely remove" button, would cause a serious problem on your drive. as proof to you, I've removed my device many times without "safely removing" it. of course it is always preferred to "safe remove" all your devices, but in case of NTFS formatted partitions, corruption is very rare.
every operating system has a tool to check/repair file systems. I suggest you connect the device to your PC, wait until the drive letter appears in My Computer, then right click on the drive and use the check disk tool to check the file system on the drive. this would most likely repair any problem on your hard drive.