all the times 5 times a day

call non stop and when we answer the phone they listen for a sec than hang up

Same here they call wait and hang up.

I've been getting phone calls from this number randomly for the last couple of weeks.  Nobody ever speaks, only hang ups after I have answered.  If I don't answer the call, they don't leave a voicemail.  I don't think it's a business phone, seems personal.

Also, I have tried calling the number back, both blocking my number and without blocking it.  I get a fast busy signal every time.