Who called from 4254608812

Missed a call on my cell phone from this #. Called back and got a recording that it was a disconnected #

It's an outgoing number for Valley Medical Center

received 2 missed calls from this number when called back said it was not connected

got a call from this number asking me to Pre-Pay my Co-Pay before my doctor's appointment over the phone.  They say that it's a new policy to pre-pay before your actual appointment date.
Who/what company asks OVER THE PHONE to Pre-pay anything before the actualy date?
Just wondering???

I have recieved 4 missed calls fron this # this morn, they dont leave a message What is this about?