prusa i3 y belt alignment problem

Hi, i'm a bit frustrated with the prusa kit i bought.
i can't get the y axis belt aligned.. At the idler bearing, the belt moves side to side, but more to one side than the other, so it gets to the point where it pushes against the idler holder walls and it generates increasingly more and more friction until the stepper starts missing steps.. It's just impossible to avoid this. I've assembled and reassembled the Y axis a gazillion times and tried to align the belt by all means possible without solving the problem.
Now i'm trying to find a piece of wood to rebuild the platform (in the case that the y axis carriage part is the one not aligned), but i wanted some input from the community as well.
thanks

Is it a plywood prusa? You can not adjust position of the idler?

I would suggest making a simple bracket to move idler to the side.

There are dozens and dozens of different i3 implementations and kits. It's pretty tough to guess what may be going wrong on any / all of them.

Usually Y axis issues are related to motor twist. If the motor is pulled so tight that it twists in the mount, the belt will not align very well.