Reporting *****ulant transaction on my credit card account.

On Wednesday night I received sms on my cell of a ********** transaction and I phoned the call center to report it. I managed to get through and they cancelled the card. I was to told to reverse the transaction they would email me a form to fill out and sign. They would then investigate. No form has been emailed to me as yet. I have tried to phone the ***** line 5 times and spent a total of one and half hours on the phone , but I am not able to get through again. I am at loss on what to do except drive through to you offices, as no one ever answers your ***** line. Please help