Keeps calling me on my cell phone

I received a claim letter in da mail saying I had 100 gift card for walmart r target call ti claim prize lol so Icalled lady with an accent sd what's ur claim number I asked who os dis she hung up lol funny

Two cell calls in one day.  Both ignored (not 'ANSWERED'--ignored)  Didn't leave any message(s).  Have HEARD if you answer these (even once) and even if they're 'robo calls', the person (or the equipment) will log that your number answered at x:xx time & will continue again/again/again to try to get a human on the line.  In our area, there are ads from several law firms stating "...up to $1500 for unwanted calls!!"  Hmmmmm.  just a/b worth a try.  Even if I only realized $50...heck, $5, from pursuing, would be worth it just to yank some chains? The "Do Not Call Registries" certainly do -0-.  Have had several lands AND all cells registered & re-registered for YEARS....maybe it IS 'cutting back' but certainly hasn't stopped the flow---which seems to be escalating in 2015???

Continues to call not answering questions

This number called my cell phone.  I did not answer since only my friends have my number and I did not know that one.