Bogus Offers and Hysterical Billing

Having recently moved to a new home, I signed-up to Xfinity for my home internet service. I also signed up for two cell phone lines. Each time I called into the Xfinity store I was offered  range of different, confusing promotions involving a bewildering range of discounts and credits. In the end, with 1GB speed home internet and two cell lines I was offered a deduction on the second line and a $400 credit off a new iphone 15. Unfortunately, once the bills began to arrive it transpired that the promotions did not exist. I raised this with staff members at the Xfinity store who sold me the contracts but they were unable to help at all. I escalated it to the store manager who established what had happened: he said that I was offered two promotions I should not have been offered. He estimated the value of these credits at $640 and told me that he had raised a ticket to have this issue dealt with. He said that he would call the following day but was less clear about when it would be resolved. I pointed out that I had Xfinity bills coming which were about twice what I was told they would be. A week later, having had no response from Xfinity at all, I called the manager. He told me that he now thought that Customer Service had lead me astray and that his staff were not at fault. When I pointed out that who was responsible or at fault was an internal Xfinity matter and that I was concerned about bloated bills I was facing, he reiterated that it was not in his control. I asked how I can escalate the matter, he was unwilling or unable to help beyond telling me to contact Customer Service.