I was called to change my gas service to spark and same a minimum of 8% off my gas bill. I signed up in anticipation of the savings. The first month I saved 8% the second month I save 13%, so I was satisfied that they were charging as I had anticipated. The following three months I did not check my bill. The bill was high but it were cold months. Then I checked again and realized that they then charged me 72% more then what I would pay Nicor. Each month after that Spark Energy charged as high as 81% more than Nicor and as little as 64% higher than Nicor. When I realized this I tried to negotiate a change. They put me off for three months telling me they would adjust it but it will take two to three billing cycles. Finally I simply canceled them and they came back with the full charge owed. I had paid my bill for what I would have owed Nicor but Spark Energy insisted I pay the full amount. In the end I paid 64% more for Spark Energy than if I had stayed with Nicor. One of my converstaions with a representative told me that they can not get the gas cheaper then Nicor and they have to make a profile! NEVER us Spark for any of your energy needs they will take your money when you do not suspect it and are very poor in the customer service.