My realestate entered my rent onto their system wrong twice. one they picked up on but one they didnt. I was lucky i technically never fell behind as i made sure i was still aweek in advance when we paid rent. The RE never picked up on the s2nd lot of rent they entered in wrong. It wasnt until i asked for my tenant ledger that i noticed i wasnt as far in advance as i should have been. So yes it is possible that they can miss this.

You should only have to pay the $330 which is what the rent was when it was missed. They should atleast give you some extra time to gather this money together(like they would if you have a rent increase and have to pay extra towards the bond)