College Student Receives Email of the Lost
Most cell phone companies have a "1 minute minimum" on all inbound calls whether you answer or not. I remember one month with Sprint where I almost ran out of minutes - so naturally I turned off my phone for the last few days.
I still got "overage fees" because the inbound calls to my voicemail charged exactly one minute each.
So if I used a phone-dialer and called you 50,000 times (then hanging up immediately), I could probably still cost you a significant amount of money. 50,000 isn't unreasonable if it takes 40 seconds to go to voicemail and you don't think to call and have my number blocked. If you give up and hang up the phone, I could make 500,000 calls in a month. (Theoretically)
I'll bet the cell company would rebate the fees though if you complained about it.