Way back - like 30 years or so, when Spark was known as Telecom (IIRC) - it was possible to add 'alias' phone accounts to one's main account. Like, if your main account was idiotrump@xtra.co.nz, you could also add another four or so aliases to that main address, like moronictrump@xtra.co.nz, spacewastertrump@xtra.co.nz, and so on. Any mail directed to the alias accounts would arrive at the main account.

Problem for me now, many years later, is I'm getting heaps of spam at those 'throwaway' alias addresses, so I'd like to close them. How do I do that? I'd prefer not to call 0800 22 55 98 and spend hours on hold if I can avoid it. Advice please.