It's an office in which taxi drivers wait for the costumers to call. What is the name of this office?
I'm not a teacher, but I write for a living. Please don't ask me about 2nd conditionals, but I'm a safe bet for what reads well in (American) English.
I am not a teacher
In the UK it's a taxi office.
In the US it's called a taxi! Most cabbies wait in their cabs until the dispatcher calls them. The 'dispatcher' sits by the telephone; the taxi drivers usually spend very little time in the dispatcher's office.
That's fair enough but the OP asked about where taxi drivers sit waiting for customers to call. Like Amigos4 said about the US, in the UK they usually stay in their car and wait for the despatcher to come on the radio and tell them where to drive to next.
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.
We have minicab offices in the UK. Minicabs are different from regular taxis- you cannot hail them in the street, but must contact them through an office or by phone.