As a PhD student, we are allowed to have certain amount of funding from school. Last year, i don't even spend one cent for printing. No one say anything. But this year when i need some money for data collection, all school staff start complaining and blaming me spend too much. say i am a problem to everyone. even though i have only use half of my funding. The money we don't use does not come to next year. If you don't use, that's your loss. so i was wondering where the money go to after that.

Yes this is a common problem. The money gets kept by the supervisor to use in the next PhD project... If you really want to use your funding, then you have to clearly state your case i.e. how much you've used and what you need the money for and what the predicted outcomes will be. If the money is still not forthcoming, then you can check your university policies and speak to the head of the graduate school.