Landlord/tenant Dispute

I am badly in need of someone to give me some legal advice on this issue:

My roommates and I recently moved out of our previous apartment.
Before we moved out, we worked a whole day to make our apartment
looked very clean and like new. We then left the keys to the
apartment office in the evening (which is a Sunday). The next
Monday or Tuesday, I called the office, the staff said we did
a very good job, and there was only minor spots, for which
they may deduct some deposit.

It turn out that today I received a $390 bill from the apartment
management, deducting our $99 deposite, we still owe them $290.
They charged us for carpet cleaning ($105), painting ($150) and
interior cleaning($135). When we left the apartment, there was
no damage except some wear-and-tear (we stayed there for two years).
It seemed they charged us for all the normal maintanence they should
pay themselves.

They said if we don't pay in 30 days, they will turn it to collections
to enforce it.

I have never had such experience. This landlord is so mean. They
do not give us any notice before charging us beyond deposite and they
charge us for what they should pay themselves. (In our lease, it does
not say they are entitled to charge us beyond deposite. But the problem
is all legal documents I found only talked about deposite.)

Could anyone give us some advice? Thanks so much!!!