a bug in my apartment that I had never seen before

Within the last 2 weeks I discovered a bug in my apartment that I had never seen before.  I requested to be put on the exterminator list.  The exterminator:  (Will), didn't find any bugs but went on and sprayed and mentioned that a tenant on the 5th floor had and an in festive amount of bedbugs in the apartment about 3 weeks ago.   After the exterminator left, that night I found 2 bed bugs and some bed bug baby shells in my apartment between my chair and air mattress.   (Along with the bite marks.)   I took picture of the bed bugs (and still have the photos).  I reported it to the apartment management.  I was told those were not bed bugs, but when the exterminator came back he viewed the pictures and confirmed they were bed bugs and he went on and sprayed and check again.  That night I found more bed bugs.  The apartment management told me I need to pay $1,000.00 up front immediately for the treatment of the bed bugs.  I do not see how this is my fault and how am I liable for   this.  If I don't pay, they are trying to evict me for something that is not my fault.  What can I do?  This is Columbia Tower Apartments in Atlanta GA (S.E.) 30312  I have been living in this apartment since February 1, 2011.  Never had a bug problem ever and I’ve only had 4 guests since I’ve been living here and none of them have a bed bugs. Its income base apartment housing.  Please advise soon, I do not know what to do!!!