A snowy picture is usually the result of a poor signal or a TV on the wrong input.
If this is occurring on all of your TVs, it is likely a problem with the outside lines and will need to be repaired by a technician. If this is occurring on one TV:
Cable outlet to -> Digital receiver to -> Television
Also, make sure you are actually controlling the digital receiver by pressing the cable button (CBL) on the remote before any manipulation.
If the problem persists, contact the Technical Support.