vehicle hesitates looses power between 15-18 rpm when shifting from gear to gear

What is your question?

I noticed this after having my clutch replaced. I was told last week that the through out bearing was vibrating could this be the issue? I took the vehicle back to the place I had the clutch put in and they are saying they don't hear the vibration . Following an oil change at bell tire they advised me to take it back to the mechanic who installed the clutch. Could it be the through out bearing or something else causing the hesitation between gears? Thank you for any advise. Oh, by the way it won't go into gear all the time and trying to get it into reverse it grinds.