BAD tenants trying to pull a fast one. Could use some advice

[Dan Crenshaw]

Could use some advice with a problem tenant.  First a little of the back story:

I took my 2 tenants (they are roommates) to court back in December because they were 2 months behind on their rent. Monthly rent is $1600 and they pay $800 each.  They made a rent payment a week before the court date, which brought the outstanding balance down to $1856.  After we went to court, we had a signed consent to enter judgement in which they agreed to each pay $1109 per month (due by the 5th) for 3 months, thus bringing the rent current by March.  The first tenant paid her $1109 on time and the second did not.  When I reached out to her on the 5th and reminded her that it was the last day she could pay, she told me she lost her job and that she was leaving (typical).   This jammed the first tenant.  Since the delinquent rent was all because of the second tenant, I decided to provide a solution to the first tenant.  I told her that if she found a qualified roommate, that we could amend the lease and move forward.  She could not find someone so we had to move to option 2.  I told her that if she paid her rent for February, she could stay for half of February, since that is what was paid for.  She agreed to that.

Now the fun part of the story:

I am using a property management software for my tenants to pay their rent online.  She paid her rent for February, and everything is going fine.  That is until she disputes her own charge with her bank on February 12, and the property management company gave her her money back.  Is this legal?  Isn't this fraud? She lived in the property, then right before she leaves, she gets a refund on the way out!  Up to date, they are now $4k behind on rent and caused about $1200 in damages (above and beyond normal wear and tear), and their security deposit is only $2400.  

Has anyone else run into this and does anyone have any advice then could lend?