Charge for paying rent in multiple payments?

[Alyssa K.]

The lease states tenant is required to pay rent in one payment. Made one small payment ($400), ignored email stating that partial payments are not allowed per lease and to please cancel the payment (Cozy doesn’t give landlord option to do it on my end), and made remainder of payment ($1350) 2 days later. The processing fee is only an additional $3, however as these tenants have been a royal PITA thus far, and it’s increasingly apparent they will need to be continuously trained, I’d like to charge a fee for them breaking this rule in the lease; however the lease doesn’t state a consequence or fee for paying in multiple payments. TAR Lease, page 2, section 5 D. Would it be reasonable, and allowable, to charge a $50 administration fee to ensure the lesson sticks and remediate my wasted time?

[Jason D.]

@Alyssa K. I dont care how many payments are made, but if it's not paid in full by the 5th, I charge a $50 late fee.