keep calling, but no message left.

We keep getting phone calls from this number every single day at 11 AM when we pick it up there is no one on the other side,
or at least it is silent. We stay on the phone now to see what happens and in about 1 minute or less we then get a hung up tone.
We hope more people report this nonsense so that perhaps the telephone companies can put an end to it.

The number 770-442-2278 is being used by a company representing One Call Diagnostics. This morning 5/5/14 at 10am I got a call from Christopher to set up an appointment for medical testing ordered by a physician about 5 weeks ago.  The number I am supposed to call back is different from the one used to call me from.  The number associated with my calling back is  866-626-7243.

A call from this number saying they were One Call Medical. Verifying a scheduled apt I'm having in VA when this number is from Georgia

Answer the phone and can hear people in like a call center and say hello and they hang up?!?!