I was one day late on a payment and 2 days later had a letter letting me know if payment wasn't made within such and such date, they would turn off electric service. I don't understand the urgency of that, but I was charged $5.00 for the letter they sent. Come on, REALLY? Other than that, no complaints. I was late on the payment because the due date is too close to when they billed me. Just looked over it, considering I have other bills to pay.
The website and information on your energy plan is not easy to access and not all of the features work. Also upon further research, frontier is not very green friendly. the prices for my area are very affordable than the other options though.