Timing Belt Noise

so, i had the timing belt and v belt replaced about 2,000 miles ago. as soon as i drove away i heard some noises. and there was this humming-almost like a vibration throughout the car. i asked u guys, and then took it back a few days laster. i was told that its because the new belt is so tight. well now its 2,000 miles later and the slushy sound, and the squeeky sounds are getting louder. what do i tell my mechanic? i know my car, and it has never sounded like this. i hear it the whole time. and i think the squeeky sound is coming from the thing that the belts turns on.... i forgot what thats called. (like a lazy-suzy turned sideways that the belt rolls/is guided on in a few different places). also, the car starts perfect like always, blows no smoke, and fuel consumption is about the same. i am getting a few MPG less since the job, but that could be my driving.
anyway, any help or shared similar experience would b great. thanx u guys!

Find out what's wrong before you have a real problem (broken TB). Take it back and comlain or find another garage. Could be as simple as TB installed incorrectly.

From your description it sounds like the accessory belt tensioner is making the noise. This can be a DIY replacement job as it is just three bolts. No complicated disassembly required.

As for the MPG loss, it could be many factors. One of those factors is where the injection timing was set during the belt replacement. It may be within specs, but a variation in where it is now vs. before the replacement can show in a variation of MPG. VAG-COM or equivalent is needed to be able to determine if the timing is a potential explanation for the drop off.