How to continue on the Exeter wait list?

I got the decision email saying I’m invited to join the wait list for Exeter, but it doesn’t say how to join.

“Detailed information has been mailed to you with instructions for communicating your continued interest”
That’s all that is said, but I haven’t been mailed anything other than that one email.

The exeter admissions office is busy every time I call, and I can’t get a hold of them.

Anyone else get put on the wait list? How are you supposed to continue?

Daughter asked Exeter through email yesterday. They replied today.

3 years ago they sent a packet or letter which had instructions for continuing with the waitlist or not. I think there was a postcard to send back. We are still waiting with (acceptance) info from a local day school, so it could take another day or two for USPS to deliver the letter to you.

I recieved a letter in the mail (yesterday? the day before?) that had a sheet of paper in it. You indicate on the sheet of paper whether you want to stay on the waitlist and then you send it back.