My tenants broke their month to month contract after 15 days.  They received keys on May 1st at walk thru. A couple of minor things needed to be done but listed on walk thru to have tentative date scheduled which they signed off on and agreed.  Later I found that they were still trying to save their soon-to-be foreclosed home but yet signed contracts with us unknowing that they were trying to still save their home.  They are threatening to sue for the whole amount given $3000 for 1st and last month rent but their date of vacate is June 15.  They refuse to paint back two rooms and they want to make a deal to give back keys on June 1st with the return of $1500 or they will proceed with litigation. I wrote a letter to agree but have changed mind since then and wrote another letter stating changed of date of walk-out inspection to June 15th as agreed prior.  A stipulation they have stated in a letter is that they could not move in due to the counter top stove being installed on May 12th, however, on the walk-thru inspection paperwork it states that it was to be replaced.  It did work at time of inspection but was not updated as the other newly replaced appliances.  I agreed to replace it but I listed stove "to be replaced" on the inspection log and neglected to list "working" at time of walk thru.  Do they have probable cause to sue, do I have to prorate their amount if there are no specifics on contract about termination only that tenants have paid for first and last month's rent and if I do need to prorated rent what is the time frame for the return to be received??