PXR5

In January 2010, we booked a return flight with CT TRAVEL on Corner of 2nd road Boon Eua Shopping Plaza, near temple and walking street.
My wife flew to Europe, but did not come back to Thai.
We cancelled the flight with Air Berlin, who refunded CT Travel, since we had paid cash.
After some mails without answer and phone calls without help from CT, we came back to Thai, and went today into their office to get our money back (10.930 baht).
CT Travel keeps on saying that they did not get the money. Air Berlin says, they did refund this company.
It seems to me that CT Travel is most unserious, stealing money from people.
Make sure you never have to deal with them.
Does anybody know how to proceed here to get our money back.
See a lawyer ? Go to the police ?
Who can help us please.
We do have all the papers, proving we have paid, and proving Air Berlin sent the money to this doubtful company.
Thanks for your help.