Hotel greed

Last year my client booked me into the Premier hotel on kempton park. They paid for this. The hotel did not believe the proof of payment. They demanded extra payment. Which I did. This all happened late at night when I was extremely tired. With the manager not being compassionate at all. Now it's a month and a half later and they still have not paid ne back for the double payment made.. I have staid in more than 300 hotels and vow not to use these greedy people again