Have you asked the place where you got it serviced? I would take the machine back and tell them that you don't understand why the machine is still so noisy.
I once took my Bernina in for cleaning and service and I don't think the technician did much of anything (except charge over $100!). When I got it home, I realized he had not reset the upper tension to factory setting -- which I assume is necessary if you are really checking into the stitch quality and timing of the machine. It makes me wonder if your service person actually lubed and oiled the moving parts. Typically the parts that get oiled are where metal meets metal; the parts that get lubrication are the gears. Newer machines have sealed bearings that never need oil. I don't know what exactly your machine needs in terms of oiling and lubrication. It is simply my suspicion that the service tech didn't do a thorough job. Machines do get noisier with wear and tear, but I wouldn't think that would happen within the period of time your machine has been in existence.
My best guess.........