money from bank

This company withdrew $300.00 from my checking. When I contacted them , they had no record or account for me or my spouce. Asked if they could please refund our money. After 4 faxes and 3 e-mails sent to them, they say they never recieved, we still have no satisfactory results. The bank cannot refund our money because there was not a check written, and they have already recieved our money. We live day to day and am very upset that they can just withdraw money from our account with out our authorizing it. They know we do not owe them this money, but refuse to give the money back to us with out a fight.