I am an Ambit consultant and could not disagree more.
I have called Ambit customer service line about 4 times in the last 2 months with various questions and have never waited more than 5 minutes for a representative.
The billing cycles are determined by the meter read dates. The meter reads are done by the delivery company, not Ambit. In my service area this in Oncor Energy and they read the meter for TXU, Reliant, Green Mountain, Bob's Energy, everyone. The only difference is who they upload the meter read numbers to for billing. That is why all customers have a 2.00 and something cent read fee on the bill. This is what Oncor charges the retail providers for the meter reading services.
The current Ambit policy allows for one late payment every 6 months prior to any sort of disconnection action. There is also a partial payment plan available to customers who are in need of more time to pay.
If you want to see a real world Ambit bill, please feel free to pull mine up at