The caller left no voice message

Received a call from 'John' indicating that there would be service reps in our area, etc. etc... I asked to be removed from their call list, and was told that they would. However,he refused to provide either his full name or the name of the company. (I used my phone's call log to locate the number)

two calls in the last two days.  
answered the first one and heard someone in the background talking about different plans, that was my queue to hangup.   did so right as someone come on the line.  

did not answer the second call.