A word of caution, there FF: just be absolutely certain that you process the "returned" file through a very good AV software. Whether intentional or not, many of the file types listed allow for the embedding of quite destructive malware and viruses. Given you don't "know" these folks, and it's a free service, the actual personnel on the other end are quite capable of doing malicious things, unbeknownst to you and their employer.
Always use a condom when transmitting or receiving transmitted files. It's not the history of your partner, it's the history of all their partners that gets you....
