TUCSON - UniSource Energy Services is warning customers to beware of phone scams involving callers who falsely claim to work for the company.

Dozens of utility customers have reported receiving such calls this year. In most cases, callers claiming to be UniSource employees tell customers their electric service is in danger of being shut off because of unpaid bills or because their electric meter needs to be replaced.

Callers instruct customers to make payment over the phone with a pre-paid money card to avoid having their power shut off. Some customers have reported receiving text messages with similar demands.

UniSource does not collect payments by such methods, spokesman Joseph Barrios said. Customers are contacted by phone only for automated bill payment reminders.

Also, the company never asks customers to purchase pre-paid money cards to pay a monthly bill.

Customers who receive phone calls or text messages like these are encouraged to contact the Arizona Attorney General's office at (800) 352-8431, or to file a consumer complaint at azag.gov.

Electric utilities and natural gas providers across the country have received reports about these types of phone scams over the past few years.

Similarly, law enforcement and other government agencies have recently reported that phone scammers are also impersonating employees from the Internal Revenue Service, U.S. Immigration and Customs Enforcement, Arizona Attorney General's office, Mohave County Superior Court and Coconino County Sheriff's Office.