Dish Network Solo Receiver Billing

It is almost 5-6 years I pay for solo receiver that i have never have during this time. Dish Network charge me every month $7.00. Today by the way I discovered mistake. I asked Dish Network represantative to give me a credit for all months and yers. He said that his record shows that I have solo receiver!!! But after checking he was agree that I did not have it. But he refused to credit my account! It was not my mistake!!!! I will submit a complaint about dish network immediately and their billing!!!!