Chase Home Finance LLC Kept my check and won't refund my money Colombus, Ohio

I received a letter in the mail stating that I was almost past due on my mortgage payment. I was sure I sent it in, but I thought it may have gotten lost in the mail.  To be sure I did not get a late charge I paid my payment online, after speaking to a representative.  She assured me they did not receive my check, and to go ahead and pay it. 

The security questions she asked me were VERY unusual.  She asked me if I owned a certain car in the past.  She also asked me where my uncle lived.  These questions are not things that she could POSSIBLE know, so after this phone call I became very suspicious.

5 days later I look on my checking account and notice that they HAD gotten my check and indeed cashed it, overdrawing my account and putting my money to -1,100 bucks.  I hastily called them and asked them to refund my payment to my checking account, which of course they refused.

I have to mail or fax in a copy of my checking account showing both payments. I will do so, but I am not expecting them to give me back my money. If they do not, I will sue them. I will also try to find out why they were asking about my uncle.

If a lawyer reads this, please let me know if there is anything I can do. Thanks.