From Mediafire
This might explain a few things
There is currently no time limit on how long uploaded files will be stored as long as you access your account (i.e. login to your account) at least once every 60 days OR at least one of your files is accessed (i.e. downloaded) every 30 days. If your account is not accessed within the time limit, then the files in your account will be cleared. MediaPro subscribers uploaded files will remain forever as long as the account is active.
If you are a Mediafire free user and your files were deleted due to inactivity, they are deleted from all servers and cannot be retrieved.
This might explain a few things