how do I get my money back that I was double billed on for over two years.

Sorry, nobody here can help you with that. You'll need to call DirecTV (phone numbers below).  I suspect your main challenge will be proving that you've double-paid after all of this time. Good luck. 

You have a charge listed on your bill twice or you were getting bills for two separate accounts? Might be some other guidance to give depending on exactly what the "double billed" situation is.

Be prepared that like most companies their Terms of Service include a timeframe for billing disputes. At over 2 years that is well beyond that time. So might mean they might only meet partway or decline any credit, but only fix it going forward. The intention being is that as the consumer you are responsible for reviewing your own finances and bills.