First thing I would try, is to try a few of the files that people have reported as corrupted on my own computer, providing I had the originals of those files. While you don´t say which file formats these files are, if it´s a movie then try play it, if it´s a zip file try to extract it etc.
If it works on your computer when trying this, something happens either on the way to the server or on the server.
To see if it´s on the way to the server, I would try different ftp programs to upload them. If they still are corrupted when downloaded, then ask the techs to look into it.