I get daily calls from this number, but its always a silent hang up call. Caller ID says Quinstreet

I just got another one. No answer, no message.

Received 3 phone calls right in a row to my personal line, which I hardly ever use. I'm not even certain of how someone got this phone number. There is never a message left and they call 3 times in a row before giving up.

I called the number back and it's a recording of "Thank you for calling Clint Street. We can assist you to drive your business forward. Press 1 to be connected." Definitely a sales call, but I'm still unsure how they got my personal line...