A tenant didn't pay rent on the 1st of the 1st month of new lease

[Seung Don Hong]

A tenant didn't pay rent on the 1st day of the 1st month of new lease. I looked at our lease agreement, and the due date for rent was left as 'blank'. The due date for the rent is supposed to be '1st' each month and the lease agreement should state that. My realtor made a mistake of leaving it as blank, and I also made a mistake of not checking it beforehand. I texted the tenant to pay the rent by 2nd and also sign addendum with due date of 1st each month. He hasn't responded yet, nor deposited the rent as of 3pm on 2nd. The lease agreement doesn't specify the exact due date, so he doesn't have any obligation to pay the rent by any day of the month. Am I right? Today being Friday, next Monday will be already 5th. I don't know what to do. I can't enforce any late fee penalty nor eviction process whatsoever at least until the last day of December? Should I take it as a pricy lesson and assume the due date for the rent is 30th or 31st of each month and enforce if he still doesn't pay the rent? I am stuck and don't know what to do. Any advice or comment will be greatly appreciated.