Email is just fine. It lets you address things as you like, puts no time pressure on you, and gives you a written record of your discussions. It's also low-overhead and universal.

Don't blame email, if you can't create a few simple inbox filters to manage the cruft for you. It has been many years since people actually suffered from the weight of zillions of spam messages in their inbox. We've largely addressed the spam thing. The non-spam stuff is going to be dumped on you, whether it's in email or phone calls or text messages or instant messages or facebook messages or instagram messages or whatever the fuck it is teenagers are doing these days that makes email "irrelevant".