Residents Energy -- Profile Analysis

My 84 year old mother in law was talked into switching from ComEd and promised savings on her electrical supply. The first 6 bills had very little discount. The bills after that jumped up and are destroying her budget (the bills use to be about $150-$180 per month and jumped to $276 and $341 for months 7 and 8). When we call Residents Energy and tell them we want to cancel our agreement, they tell us that we are not locked in and can go anywhere. When we call ComEd, they tell us they can't take us back because the account is locked to Residents Energy. I feel that this company is targeting the elderly because they are more likely to not fight them.