Since September, an article on the website MoneySavingExpert warned of its default setting Facebook for automatic reproduction video could inflate consumers' bills as videos use their mobile connection. 
At that time, Facebok said that when updates to their app will not make any changes to the user's settings, so if someone has chosen auto-play, the setting will remain unchanged.
However, with the combination of iOS update and app updates, videos start playing by themselves as the device regains the default settings that autoplay allows. It may sound small, but think about this:
On a phone, where an average Facebook user, with regular, daily interactions on social network, mostly for personal use, his phone's average data usage would have jumped from 3GB to 6GB per month by, without changes in usage patterns.
If of course we think of a Facebook user, who does not stop checking his timeline, for personal or business reasons, the monthly accounts of will go up an average of 9GB above.
You can change settings from the Facebook app to iOS and Android to stop the autoplay of the videos. You should check your settings whenever there is an update, no matter what the companies promise. Of course there are other applications that run automatically, and you should disable their Autoplay capability.
