Let's say you get orders for five lots of tickets a day - easy - you stick em in an envelope, pop a stamp on, and bob's yer aunties live in lover.
You then have to start issuing refunds - and if there's 300 tickets to refund, that 300 e-mails to read - x number of cheques to write - making sure you've crossed everyone of the list as you issue them, making sure you have enough cheques, refunding Paypal payments, dealing with Paypal claims.... not easy for inexperienced promoters who let's be honest jumped in with both feet without having the good sense to work out exactly what it would involve...
As for being a former junior accountant, don't they call them 'teaboys' around your way?