Should I post 3 day notice?

[Niki C.]

Hi BP family,

I'm a new landlord and my very first tenant is having problem right now. They've been living in my condo starting this Sep, paid on time on Sep, late on Oct (reason given : somebody stole their money from their bank), on time on Nov, but now will not pay till 8th of this month (reason given: been 3 months maternity leave), and ask me to waive the late fee so I said NO. 

My question is even they let me know they will pay the rent plus late fee this Friday, should I still post 3 day notice or any other form I should use to clearly tell them that paying rent late all the time I will start eviction process?

i really appreciate all the advises.

Thank you.