What are my rights as a renter when it comes to Automatic Rent Withdrawals?

I am renting from a property management company. I signed up for automatic rent withdrawals over a year ago. Everything has been going fine. I noticed a few days ago my rent had not been taken out, but I figured it was slow to post online. Then I get a letter from the property manager saying we are delinquent on our rent payment for this month. The automatic payment didn't work! We have sufficient funds in our account, we have always paid on time, and we never gave anyone authorization to terminate the automatic withdrawals. I am afraid my property manager is going to say its my fault and still make us pay a late fee. What are my rights as a renter when Automatic Rent Withdrawals does not work and my property manager wants to charge me a late fee?