If you do the reset properly, it will start the process after a few presses. But it does not work straight away all the time. You could try it again. Unless you mean that it worked and then the light came back.
When it works, it will start flashing and you will know that it does something. Once it is done, it will be gone.
There is no timing chain recall. So you will not be able to fixed it like that. Having gone through the airbag/seat/struts recalls and being left with a vandalised car, with a rocking seat and the airbag dead with the light constantly on, maybe it is better that they did not do a chain recall to vandalise all cars.
You can read the angle whether it goes beyond the urban legend 10 degrees.
If the chain needs replacement, the dealer may cover part of the cost. It may be cheaper to cover the whole cost and do it independently.
You need £1K+ at the dealer.
Lots of people have posts on forums getting money from Mazda.
http://www.mazda6forums.co.uk/index.php?topic=1867.0