I would send it back, i probably handle more hard drives on a daily basis than anyone, if i drop or damage one i have to send them back to the manufacturer at the end of each month, just not fair on the customer to send anything like that out. I bet i have to pick up and fit upwards of 100 hard drives a day some days upwards of 500.
We have tested all sorts of drops and knocks to see what deliver a lethal shock and its the hard on hard that causes the big damage where the g/s is very high.