Comcast XFINITY Comcast offers POOR customer service and rips its customer off Southeastern, Pennsylvania

I have been using Comcast for more than ten years. Their customer service has been getting worse and worse. Sometime in June 2012 I called Comcast and told them I would be moving from PA to MN. They told me I must disconnect my service in PA and then schedule a new service in MN. I told them to disconnect my service in PA on July 20, 2012. They disconnected my service on June 20, 2012. It took me a couple of days to clear that problem. Then, they billed me on June 23 for $128.49, despite the fact that I already paid the bill in full ($68.55) on June 5th. After I paid another bill in full ($68.55) on July 6th, they billed me again on July 13 and then July 19 with a huge amount. When I talked to a Comcast agent (Sherry) in June to discontinue my service on July 20, she told me not to submit any payment after I paid the July bill. Unfortunately, Comcast charged me twice in July. When I talked to a supervisor "Leah," she said the information from "Sherry" was not correct. Without  realizing that my bank had already paid $68.55 on July 5th, I made another payment ($59.49) on July 23, 2012. When I received my bank report and found I paid twice in July, I called Comcast about the payment. It took me almost an hour to reach an alive person, because I was transferred from one agent to another and then got disconnected. Supervisor "Leah" refused to give me a full refund for the second payment I made in July, saying that my service cut-off date was not July 22 but July 10, which is different from the information from Agent "Sherry." Comcast is a mess now. If you use their service, you will get ripped off, such as you will be billed and charged twice within one months. So, please never, never use Comcast.