DirecTV and EchoStar are threatening the state of South Carolina with a lawsuit if $30M in taxes that the companies allege were illegally levied upon satellite TV customers are not refunded.

The Triangle Business Journal reports that the companies (really company at this point) have made the threat to conform with the appeals process for taxes in North Carolina.

The complaint from the companies is that similar taxes are not levied on in- state cable companies and therefore the tax is an unconstitutional use of state powers (since states are not allowed to work against or regulate interstate commerce).