Beg Bug treatment denied

I am a renter in a student apartment complex in Austin, TX. I recently found a bedbug in my apartment and notified my apartment about it. They told me that I am responsible for treating the problem and they said that they have renters sign a "bedbug addendum" which states that renters are held responsible for bed bug infestations. With as many students that live in the complex, it is unlikely that my apartment is the only one with bedbugs and it is likely coming from other sources. I do not recall signing a bedbug addendum since I subleased and the paperwork was separate. When I told them that I came in as a subleaser to the apartments they said that I am "taking the apartment as is" and that I am "still responsible for the treatment" even if it was from the previous renter. My apartment complex is not a part of the rental protection agency. What leverage do I have to have this taken care of?