Customer service agent attitude and unwillingness

I made a payment on the internet to a supplier in Canada. The supplier declined the transaction due to some error with the name on my card. They said I don't have to do anything my bank will reverse the money by it self. Now seven days later the money is still reserved for the payment and ABSA wont reverse the money without a letter from the company. The company just say the bank will reverse the payment on its own and does not require a letter. After explaining this to the agent he just rep**** sorry he cant do anything without a letter. SO in other words stuff you and go away.