Worst customer service experience

I have had quite a frustrating experience recently and spent over 10 + hours talking with at least 8 different customer service representatives trying to get it resolved.  I switched from a family plan to a personal account at which time I was told that the instalment plan payments for my cell phone would also switch over.  The representative at the store did a credit check and assured me that I was eligible and I was assured that they payments for my phone would transfer to my new account from the family plan account.  This never happenned and now my family is all of the sudden being charged $499 (the ramaining balance of the phone).  Each time I call customer service I am told they can clearly see that the installment plan was supposed to transfer and they do not know why it didn't, but that they are not able to fix it themselves and will need to create a case.  They assure me it will be fixed.  Each time a case is opened it is closed and I never receive a call back stating that it has been closed.   When I follow up I am always told that they will create a new case.  I have spent over two weeks trying to get this resolved and over 10 hours and am definitely going to switch cell phone providers.  This has been the worst customer service experience I have ever encountered with a company.