My lease at my last appartment expired at the end of last September and I was planning on purchasing a house. According to my lease I had to give 60 days notice of moving out but since I didn't know if I would get the house and still have 60 days to give notice I could only give the apartment a 45 day notice of me moving out. Since I wasn't planning on signing a new lease I would be on a month to month payment. I wrote them a letter explaing that I didn't have 60 days to give them and that I wasn't going to pay for both my mortgage and a months rent when I wouldn't be living there. I received a call today from a collection agency telling me I needed to pay it or it would go on my credit. What are my options for this matter?
I can't tell from your question whether you were still under your signed lease at the time or were renting on a month to month basis. Your lease will govern whether you are obligated to pay the extra month. In addition, the Texas Property Code has provisions regarding month to month leases.
The collection agency and their activities are a separate issue in that there are rules regulating their activities, even when the debt is legitimate and owed.
As a practical matter, it may be possible (if you in fact owe the money) to simply work out a payment agreement with your previous landlord. That could stop the collection activities, preserve your credit and hopefully keep your former landlord as a positive reference in the future.