help needed, please!

Hi,
My case is: I moved into a building around one month ago. Yesterday evening I moved my mattress and TV into my apartment. But today the manager of this building told me that I’ll have to pay $500 fine for yesterday evening’s move-in. Her reason is that I violated this building’s rule because this building does not allow move-in after 5pm. I feel it’s not fair because of these:
1, Before my husband moved our stuff, he checked the front desk and was going to ask the doorman if we could move our stuff, but the doorman was not there at that time. He didn’t show up and tell my husband we could move in our stuff until we were almost done with the moving.
2, We didn’t damage anything with yesterday evening’s move-in.
3, We did receive the manager’s information package for telling us this building’s rule, but we thought we were just moving in our personal stuff, not like our first time’s big move-in. Plus, it says for all kinds of violations, the fine is $25-$500. It doesn’t say which kind of violation is for how much fine.
So, we think we should not be fined or shouldn’t be fined that much.
In addition, we think we were discriminated by the manager because we are Chinese. When we first moved in, she designed us a smallest locker, even we saw there were two vacant normal size lockers in the locker room. For yesterday’s situation, we think she should have only given us a warning but not given us such high amount of fine.
Please tell me if you have any idea to help us not to be fined or be fined as little possible.
Thank you very much!