Simply replace the unfilled areas such as "" and "[date]" with your information.
This letter concerns your late rental payments. [Name of company] does not tolerate late payments from any of our tenants and if this continues, you will be in breach of your [rental/lease].
In your [rental/lease] agreement, you will find a provision that clearly states "[Quote from the Rental/Lease Agreement Concerning Late Payments]."
Please consider this your final notice about this matter. Further delinquency will not be tolerated.