Tenant Late With Rent (Updated)

I spoke with my property manager yesterday and discovered my tenant is still late with his rent. Last week, he paid $550 of the $750 and said he'd pay it all by the end of the week. Since then, we've received $100 from his church to go towards the rent. While my PM was checking her computer system, she saw one screen that said he was all paid up and another showed he still owed money, so she was going to research that some more and find out the real status. However, she did sent out a nasty letter and spoke with the tenant and told him we need to stop this late payment habit. His cell phone is occasionally disconnected, so he's obviously got problems paying his bills.

The tenant's lease clearly states that, in addition to the late charges he has to pay, if he has not paid the rent by the 15th of the month, he is to move out or he will be evicted. I told the PM to enforce that rule next month. I am also faxing that directive to her so she's got it in writing.

Update: In my fax to my PM, I also said that I was concerned that in some states, accepting partial rent makes it legally more difficult to evict someone and, if that was the case in Oklahoma, to stop accepting partial rent payments. I just got an email from her saying the current small claims judge doesn't discriminate on eviction based on partial payment and that she has personally evicted several people who paid paid rent only. So that's a bit of good news for me...