There is not much you can do that I know of since phone lines were designed for voice and not data. I would check all connections. If you call the phone co. they will want an outrageous service call if it is not in their line.
Try a hard reset...Unplug receiver while it is on count to 20 and plug back in then run a check switch through your menu options. If this doesn't correct the problem replace LNB. It is easier to find and replace the complete unit most of the time.