Has called me 3 time but leave n message

Called me 4 times but after I say hello, it goes beep and then they hang up!

this number has called me 5 x times to day  in 8 hr

I got 4 calls from this person.  Then again I have metro pcs.  Who is this person calling?  I answered then I heard someone say " hey"

get calls all day from this number....I never pick it up because i don't recognize it.....They never leave a message....I called the number at 330 AM this morning and let it ring 5 times and hung up.  I hope I disturbed someone's sleep.....especially if it's a prank call....