AAFES Bad check repayment

[djnikki1]

I am in need of assistance.  I have two bad checks that were cashed at AAFES. I received a notification letter and repayment letter on June 9 2010 and they totaled $375.  I have been paying down on them.  I called them in February 2012 to get my balance and I was informed my account had been sent to collections last year. Yet AAFES still continues to cash the payments I have been sending.  They stated they sent notices, but I never received them.  The only notificaiton I received was the one from June 2010.  They stated NCO sent me letters, but again they never did.  I informed AAFES of this and they stated it wasn't their problem and that I could send copies of the letters I received but it wouldn't make a difference.  They stated my balance with them was over $300! But that's untrue because according to the letters they sent me in june 2010, the remaining balance was $203.  I only receive Social Security disbability and care for my two children with no child support. So I sent payments when I could.  What should I do?  I feel its unfair for them to increase my balance, never send me notifcation letters and NCO never sent me letters.  They stated they send the letters to whatever address DEERS has on file, whenever I move I always update my address with DEERS.  So going by their statement that means they never sent the notices.  They sent a treasury offset and took $173.55 from my social Security for this month without sending me a notice.  That means according to the letters they sent me, my remaining balance is $30.  I have contacted their headquarters because I feel they are being unjust.  What other steps should I take?  I need to get this cleared ASAP so I can use my STAR Card to book an airline ticket for April 24th.