File version history would allow you to restore an older version, however it does require having at least a Pro account to have this feature available.
The number of versions kept within the version history depends on the account level of the file owner, as well as the settings decided upon by your account administrator. By default, the number of saved file versions is as follows:
Personal Free - Unavailable* Personal Pro - 10 Versions Starter - 25 Versions Business/Business Plus - 50 Versions Enterprise - 100 Versions Elite - Unlimited
Since you are under a free account, Unfortunately this feature is not available.
If there is anything else that I can assist you, please let me know.