calls leaves a number and her name.. if someone doesnt tell me what its regarding i do not call back

I have received several calls from this number and after asking who they were they immediately hung up.

They have called here today 4 times so far. Its a pain when you are waiting for important calls

Cold call from a telemarketer. Same experience as the others

Caller asks for me by name then goes on to say he is calling to update my ex-wife on her claim status. Wouldn't say what kind of claim or how he was calling me.Would not say where he was from. Googled number and found out it's a collection agency

Asked for creadit card number and CVV2. Citibank sais it is a fraud and offered to reisuire card.

I've been getting phone calls from this number!! Unfortunately, I picked it up in time only to hear a generated female voice saying, 'thank you for calling' and hangs up later. Very ANNOYING!!! Who is generating these calls? How do I stop it from calling me again?! I've received 2 to 3 calls a day, every few days for the past few weeks.