Complaints about billing

Has anyone else had problems with the billing? I recently had to return my old cable boxes to Xfinity due to an unexpected move and had to get new ones. I had to cancel my old service and pick a new plan because the old triple play plan was gone. Someone recommended the next gen plan which I thought was supposed to save me money, but it didn't. I was told over the phone by one of the agents who didn't speak English that it was under 200.00, but when I saw the first bill in an email it was almost 400.00! I immediately called them and changed plans and once again they told me the plan was under 200.00 but a month later once again, the bill was a little over 300.00. I called them and they assured me I didn't have to pay that much, but the bill has yet to be changed. What is going on? Is this bait and switch or false advertising, I'm not sure which. Also, I'm getting these outrageous paper bills for an account that I cancelled last month. What is going on? Could someone please help me?