Drawing file is not valid

Hello !
About a month ago the HDD of my Acer 7750G laptop decided to teach me a lesson about backing up data and not putting all the information on the same data storage device no matter how reliable the classic HDD has become.
The hdd failed and I tried to fix it with a recovery software and damaged it even further. I took it to a data recovery firm and they managed to recover some data but most of it is non usable(I am referring to .dwg files). The following message appears when I attempt to open a damaged .dwg file:

“Drawing file is not valid”