You may also want to include bullet points of what is in progress so that your client knows you’re on top of things. That will also likely reduce the amount of emails sitting in your inbox when you return. Unlike a more generalized email (like the one I’ve provided) that you can send en masse, you’ll want to set aside some time to send more personalized emails out.
I meant email. The phone calls were similar, but a whole other problem. Your overdue notice? Did you discuss it with Head of Circulation (who knew the background)? No? Let me transfer you.

I only set my out of office if I’m going to be gone for more than one full day. Like, right now I don’t bother if I’m going to be out for one day, because in general the people who email me either know I’m out for a day or are unfazed by waiting 24 hours for a response. The last time I went out of office for a week, I came back to about 65 emails, 9 of which would have actually required my attention when I weeded through them. If I got a higher email volume, I’d do for a single day though.
One year my organization mistakenly left me off the phone directory. I made no attempt to correct that. The only people who could call me we’re those who knew my number; everyone else had to use email.