They just told me to cut the USB-plug and send it to them just for an insurance that i couldn't use the old mouse anymore, but i got the new mouse before i had to do that.

Sure, a G25 is more expensive than a mouse but you can always try

Quote from Racer325 :

I didn't buy the wheel from logitech aswell, so i dont have a reciept.

It's not necessary, they just needed some numbers from under the mouse (under the G25 in your case) and after that they just sended me a new mouse, and i didn't even bought it new, i bought it used from a friend. Logitech is great!

So give it a try and call the Logitech support and see if they can fix it. The worse thing that could happend is that they give you a NO

I would try to call Logitech anyway,

I have very good experiences with them. For example an optical mouse, logitech mx518 broke for me and the warranty had run out, but they still sended me a whole new mouse! that is great service!