The stuff they provide is just sugar & yeast so it is possible for the yeast to have gone bad but not that likely. Most likely you have a leak somewhere. Probably around where the co2 line attaches to the generator or a hole in the co2 line itself. Open the top, shine a torch inside & see if the mixture is producing bubbles. If it is then you have a leak. You need to find the leak & fix it.
The reaction also takes longer in colder weather so if it is very cold where the co2 generator is located it may just take longer for the reaction to happen. If the generator is in a warm place & the mixture is not producing bubbles, throw the mixture away & make a new mix using sugar & yeast. There are heaps of recipes out there for making up the mixture but stick to using just sugar & yeast.
Thanks it started working this morning after we reshook the canister, also theres a white film appearing on some of the driftwood and plants is this normal? Is this the tank cycling and shouuld we have waited to put the plants in till it cycled?
The white film is very common in newly set up tanks. It looks nasty but is not harmful. You can suck it out with a siphon if you like or you can just leave it there & it will go away on it's own within a couple of weeks. It is always best to have the plants in before cycling as they consume lots of ammonia which has an immediate impact on haw much ammonia is available for a bacteria colony to establish.
There is a small chance that the white film is fluid from the co2 generator travelling up the co2 line & into the tank. Just make sure that is not what is happening. If the fluid from the generator is travelling along the co2 line into the tank, please post again that this is happening & I will help you stop that from happening.