Rent Increase - Deduct from Security Deposit?

[Jay R.]

Hi Guys, 

I have a quick question that I am hoping someone can answer. To make a long story short. I have a tenant whose lease expired in August. I specifically let them know via certified mail in August that for the month of October their rent would increase by $50 dollars due to them being on a MTM lease now. Throughout this month a had to constantly call them because October's rent payment was late. They then told me that they would like to use "Last Months" rent which they paid to the previous landlord as this months payment and they would vacate the premises by the end of this month.

My argument to them as well as my question to you all is. Shouldn't they owe me for the increase in rent for the amount $50 dollars as well as late fees because as of the 10th I did not receive a payment (They both pay separate so that would be double late fees) and I was told after the fact that they would like to use their last month's rent for this month.

To end this long ramble ( I apologize)!! I am thinking of just taking the money out of their security deposit once they leave. Am i right in thinking this way?