KANGOO VAN?

My Kangoo has suddenly lost a lot of power . it starts ok, revs ok, but after about 15-20mph the acceleration is very slloooooowwww.. and the engine sound has gotten louder like as if air filter is half off (which its not !!)

Does this one have a turbo that may have packed in ? it is a dci70 1500 03 plate

renaults say they will look at it for £100 but they dont seem very helpful and last time they were involved they gave me the usual run round charging for labour hours when i know full well the van was in the carpark ( i was watching from over the road ) a 10 minute job they charged 3 hours for .. or tried to !!

thanx in advance to you who try !!