Bill Increase by $30/mo. Due to "Processing Error"

I changed my plan to reduce my monthly bill and was quoted $149.55 /mo. so I accepted. It took Xfinity more than a month to actually process the order and now they are telling me that my monthly will be $179.69 /mo. When I sign in to my account, I get a pop up telling me that there was a processing error, and I need to review and approve changes. This is already $10 more than I used to pay.

I want some answers. The next step will be a formal complaint with the FCC.