Very likely the water is not hot enough. I use the IngenuiTEA myself and I use a hot water spiket on our coffee machine here at work to fill it. I can only suspect the water is near-boiling, but it is my only option.
However, I have found when I have teas that take approx. 7 minutes, the water is still hot after that time. If you are using a microwave, I would try extending the time heating the water.
Someone else here likely knows more exact times to use in the microwave.