Free Service to log my games error logs to

Hello,

I'm developing a game that part of it has Real Time multiplayer matches, this part was made using SmartFox server that's installed on my client's own server, testing it in my office I don't run into problems but players are reporting problems that Real Time multiplayer matches not starting sometimes. I suspect that there might be miscommunication happening with SmartFox since the problems happen only in the Real Time matches.

Sorry for the long intro, my QUESTION is: Is there is a free service where I can send Json object to it via an API call (WWW class) and then I could check it regularly to check what went wrong on player's side? I will be sending a custom Json object that the game on users devices will make in the case something went wrong . It will be something like this {"username":"John Doe", "time":"Dec 7 2016 4:30 PM","error":"Match canceled because Competitor request response was empty"}

Thanks in advance