How to accept the fact that I lost a customer in my workplace?

I work at a popular pizza restaurant that is only in Texas, and I am still new as last week was my first week of work. Well, today was my first day that I get to answer the phone calls to get delivery orders from customers. As a matter of fact in general, I REALLY dislike talking on the phone, because I always have to make people repeat what they are saying….thus making my customers repeat and spell out their names and addresses about ten times. I get customers getting really impatient on me, and I even got a customer who canceled his order on me for delivery and (indirectly) said that he won’t order his pizza at my workplace anymore, and why? Because I was taking a long time trying to spell out his home address and taking up orders for food, and simply kept asking him to repeat unfamiliar names. And we have to use this complicated computer machine to take up orders and to authorize money from customers’ credit cards.. Basically, I made my manager mad just because we lost a customer.. I know customers just simply want a perfect service, but with me because I’m still new, they’re gonna have to bear with me. =/