Does anyone know how to fix a broken external hard drive?

I have a 500gb western digital essential edition and a 750gb wd essential edition and neither one of them are being recognized by either my mac or pc.

The one hard drive took about a 1 foot drop and the other one stopped working when I accidentally unplugged in without ejecting it first.

I called wd but they were really no help. The warranty of the 750gb hard drive has expired and I can’t find the receipt for 500gb one.

Any suggestions? I have so much info on both of these hard drives and I would be very upset if they were just worthless now and all the files on them were lost forever…