Patial Rent payment online

[Sam LLoyd]

I'm currently in a situation where I have a tenant leaving on 30 day notice...not on the best of terms.  Up to now, they have been doing online payments through Rentec Direct.  I'm worried that they will make a partial payment, and I have no way to refuse this payment short of removing the online payment ability.  If I accept payment, even partially, then I cannot speed up the leaving process by giving them the 7day late payment notice.  

Anyone have any experience/advice on this?