The customer was swearing and shouting down the phone ( He rang me just so you know), When he stopped ranting I calmly proceeded to tell the customer not to speak to me like that, I followed this up by telling the customer I didn't come to work to get abused and I was well within my rights to end the call. He apologised straight away, I completed the registration and he apologised again before he ended the call. Furthermore I got a sale so everybody leaves happy.