DIRECTV DirecTV 10 Year Overcharge to Us! Internet

Just realized that DirecTV charges $6 per month for equipment rental; I've been paying $10 since 2000.  I called DirecTV and they explained that I was a Primestar customer and my fee with Primestar was $10.  Even though I have had several technicians visit my home and swap out my equipment and re-run a cable that had gone bad not once did they make me aware I could cancel the Primestar agreement and enter the DirecTV agreement to save me $4.  Obviously, when I called with a problem they looked to see if I had the equipment agreement rental so why wouldn't they make me aware of the difference?  I actually would have thought when they switched from Primestar to DirecTV they would have sent information giving me the option to minimize this charge?  They wouldn't even give me a dime worth of credit or offer any type of "make up" since it was my obligation to switch it over - how could I if I never knew!!  Very poor customer service; I truly feel like I have been taken advantage of for 10 years and they have stolen $480 from me!!  I have an appointment to switch to dish!