
Quoting
flyingron
The landlord is not obliged to remind you to pay your rent on time or that late fees are imposed if you are late. There are limits in NC on late fees however. First, the fee may not be more than $15 or 5% of your monthly rent (which ever is more). It also can't be deducted from subsequent rent payments to make them incomplete (and hence late). Essentially, the late fees just accrue, one for each month you were late.
If the fees are legally permitted (see above), then the landlord is entitled to deduct them from the deposit.
You won't win suing the landlord.