Does Wulong tea melt fat away (20 lbs. in 20 days)?

No! These claims don't have any basis in any research or analysis I have seen to date and have every appearance of wild exaggeration.

The Chinese will not make these claims, neither the health authorities.

In support of this :

• The TV show "The Biggest Loser", employs the most aggressive diet and exercise regime to achieve extreme speed of weight reduction (which is considered to be unsustainable) .The maximum weight loss is around 3kg/week.
• By comparison, a study published by Human Nutrition and Metabolism “Oolong tea increases metabolic rate and fat oxidation in men.” reported the result of 1kg weight reduction among the participants in 6 weeks. The effect is recorded, but does not "melt fat away", ie 5% the weight reduction of an aggressive weight loss regime.