The Telephone Consumer Protection Act of 1991 outlaws certain phone calls made to cell phones. When a company uses an autodialer (a machine that randomly dials numbers–or a list of phone numbers entered into the machine) it is not allowed to call a cell phone unless it has consent from the consumer.
If the debt collector robo-calls your cell phone without consent, it may be a violation of the TCPA, and you may be entitled to $500 damages per call. Damages can be tripled if you can show that the phone calls were made willfully or knowingly.
If you’re getting autodialed calls to your cell phone, consult a consumer attorney.