I don’t understand how Sirius managed to buy Harry a firebolt when he was a widely known mass murderer. I recall them mentioning that they took the gold from Sirius’ vault and had it shipped to him. However, how do you buy something with just your vault number? I just don’t buy the Goblins would be so lax on security. Also you’d think someone would have alerted the Ministry if a mass murderer who broke out of Azkaban is making accessing his vault.
Is there something in the book I’m missing?