thre are many fake pens,hard drives coming in now...u got ur self a faulty drive..which canot be repaird ..you can try something like low level format but i dont think it will work..and you canot repair hard drives..theres no user repairable parts in it..what you can do is to try some data recovery software and see wther its detecting and recover ur files..and your drive is not getting faulty or corrupted just because you did not remove it safely..their electronics so this could happen at anytime..could be ur static current as well so forget about it...
but now what you can do is to ither throw it to dust bin or open the case and remove the hard drive and get a new laptop hard drive and fix into that case (its posible) and make sure you get a portable hard drive which comes with external power supply next time when ur goin to buy coz thos hard drives are much more stable and easy to recover and easy to change if it gets faulty...
or else if u got it brand new you can go to their site and post a complain explaining ur porblem.. i have 2 hard drives 1tera each and i registerd them when i got them and one got faulty and i sent the hard drive back to them and they replaced the hard drive and sent me bak in 3weeks...mine is seagate and i got it from austrailia ...and i have the purchase bill and details