How many messages for per diem?

I've worked per diem for about 3 months now, and so far it fits my schedule. I work about 3 8 hours shifts. However, in the past couple of weeks we have had a "bug" go around and a lot of call-ins, and a FT LPN quit. I will fill in when I can, but today (because I have caller ID), they called my house 8 times. They left 3 messages. Has anyone ever heard of this? Or are facilities this desperate?