iPhone mail-in repair has no bag in the box. What do I do?

This is the second time this has happened in my attempts to order a mail-in box repair.

The box has arrived within the correct amount of time, but, no bag in which to actually have it shipped out in has come with the box, leaving me unable to do number six.

I haven't been able to get into contact with apple otherwise- their support site just leads me through the same loops over and over again.

So, is it safe to just put in the phone without the bag?

Or can I find one in my house and use that?