The house plant section will be your best bet. This section is for edible figs, which doesn't include ficus Benjamina.

I know it's a long read, but read all of this and you'll have a much better idea of what ficus needs are and that may tell you what you've been doing wrong.

http://forums2.gardenweb.com/discussions/1476078/ficus-trees-in-containers-iv?n=213

yours may be too far gone by the pics. Even the leaves it has look gone.

was it being over watered? Not watered at all? Was it exposed to cold temps?

They're very very easy to care for if you give them the basics they need.

High light, correct soil choice, knowing how and when to water and fertilize.

Here is mine

That plant needs repotting, needs pruning back and cleaning out. You can scratch the bark layer and see if there is green under if not time to bury it.