Contour: Slow, slow

My cable tv is slow on many things.  When I try to go to Guide, Info, switch channels,... take 10, 15 seconds on each move.  When trying Netflix, HBO on Demand,... once I press play on any show, connection is so slow the display is blurry, pauses or loses sound.  Have tried rebooting and switching out Contour box.  Have checked connectios.  Have sought support by phone.  Nothing works yet.  Cox employees all advise the this isn’t the experience I’m supposed to be having.   What should I do next?