First scenario:They call and don't say anything as it is an automatic dialer. It will randomly dial numbers that are in their system and then your information shows up on the collectors computer screen. If you have a cleared account there is a chance your number was not removed from dialer even if your account was cleared.
Second scenario: They call and don't answer to frustrate you to call back. now you have called them and it's not them soliciting, it is you calling them.
617 229-5728 They call all the time and when ever I pick up silence. Once I picked up and someone spoke to me and asked for a female name with the same first initial as me and used my last name. I am the only person that lives or has lived at this number. There is no female that I know of with my same first initial either and I have a somewhat uncommon last name. I told them this and that was almost a month ago and I'm still getting calls.
I received a call from this number. When I called no one answered, but I could hear noise in the back ground. Clearly they just sitting on the phone listening. I hung up after this went on for about 40 seconds.