Bad Service from my apartment complex

This is short and somewhat bewildering.

Our rent, as with most apartments, is due on the first of the month. No sweat, right? So I walk my check over there on Saturday the 1st, and put it in the hands of the apartment complex manager.

Today I recieved a letter informing me my rent is delinquient and I owe about $30 worth of late charges.

...

Morning needs to hurry up and get here so I can go give the apartment manager an earful. I turned in my rent on the 1st, there is no way in hell it's late. I am NOT paying those late fees. I'll pay late fees when it's honestly my fault, but that is certainly not the case here.