Mozilla has been crashed many times

Hi there!
Mozilla Firefox is the latest and fastest browser for all experts and general users. So, I use Mozilla Firefox for my safe browsing.
But sometimes, my Mozilla Firefox crashes. I lost my active log-ins and some important works.
It is not restoring any option again. So, it can not warranty any page browsing. I am not satisfied.
I have reported this many times to Mozilla Customer Care. Still, my problem has not been solved.
Please give a good suggestion.
