Not to start a firestorm here, but I sorta need to rely on millennials. And it's tough. I'm in social media marketing. I'm paying kids $35-45k for about 25-30 hrs of work a week. 2 of the "kids" I've hired couldn't make it into the office before 10am. Another one simply didn't meet deadlines. Another one didn't listen and refused to create a 6 page ppt presentation the way I needed it. And by the way, all these kids seemed to be good kids. They just have no idea how to "take your lunch pale to work". Typical snowflakes.
The other 2 were administrative assistants. One didn't tell us our flights got moved to an earlier time and we missed the plane to our visit with our biggest client. Another stole from us.
Honestly, we are probably going to use to agency after Jan 1.
A good admin assistant is pretty easy to find. You can tell if they're worth a crap just by where they've worked. If they're hesitant to give the name of their last boss, pretty safe to say they were canned and they're no good. I would look for a lifer. No degree, attn to detail, first priority is protecting their boss, etc. They are out there.
Have you reached out to local colleges or professional groups in the area? Recommendations are the best way to get someone who is solid. I wouldn't ever recommend someone unless I knew they were absolutely jam up. I wouldn't use an agency, if you only need a cpl of these positions hire two people (hourly) for a specified amount of time. Then just hire the star full time and tell the other person their assignment has ended. Say 3 month contract, at the 3 month mark, tell the turd you thank them for the work and wish them well. No liability.
Do you have an HR person who is making sure you're getting rid of these "kids" the right way? Even if they suck, fire a minority and replace them with a white guy and you could lose everything. Unless they're going through an agreed upon (signed) probationary period, I would audit your process.
If you need help getting a few resumes to look at let me know. I wouldn't mind spending a bit of time on a weekend to help an alum out.