They do the same thing to me, call but never answer. I return the call and the robot asks if I want to be removed from their call list, but they still keep calling.

You can add numbers on your cell phone to a reject list- bring up the number and hit menu button there will be a add to reject list pop up with other options like delete etc.

received call from this number didn't answer.

Called in the morning, no message..

Called this morning: automated message- hit 1 to lower your interest rate, hit 2 to disconnect.  I hit 1, and they immediately said that because I paid my bill on time they would drop by interest on my credit card to 6%.  I asked which one, the response was priceless: "The visa or mastercard from Citibank, Chase or Capital 1".  Really??? That's amazing.  And then I hung up.