It has worked for me, and it can work for others too, especially if they call from their new job to announce that they don't know what to do, because they think it is their fault that the terlet got clogged, because we sent to the competition's main fax number a set of instructions on how to use a terlet plunger, suggesting that they not to confuse the terlet plunger with the sink plunger.
There is always the boiling water investigative option, which I'll bet you didn't try, because it came from a woman. Chauvanist. Kenrayc's suggestion is also a good one in the absence of the free option, but then you would have to get your wittle hands dirty. Don't dump grease down the sink anymore, because garbage disposer's don't grind it up.