who is responsible????

I live in florida. I went to a taxperparer to have tax prepared and e-file. The preparer informed me since I was a first time home buyer i qualify for a special tax credit, making my refund in excess of 5k. Using rapid refund i was given a check the next day.
I later learned that the special tax credit is only for people living in the district of columbia. The irs cought the mistake adjusted my refund. Now the rapid refund company is demanding $3600 payment immediately and will not accept reasonable payment arrangements. The tax preparer said it was an honest mistake, but she, nor is her company liable.
what should I do?????

It was a mistake made by the tax preparer, and most likely a small claims court would hold that the company and the preparer are liable for any loss you sustain as a result of the error. However, repayment of the $3,600 that you received by mistake is not a loss to you. Any interest charged on the tax due or any cost to you of borrowing money to repay the amount, would be a loss to you and the company that prepared your tax should be liable for that.