why is my microsoft wireless mouse not scrolling properly?

It is a Microsoft Wireless Mobile Mouse 1000. The mouse still works it's just the scrolling that is messed up. Everytime i make it scroll up or down it will go up and down repetitively so it just stays in the same place. I've unplugged it and put it back in again to see if it will be fixed but it doesn't. I've tried putting it in different usb ports but it still doesn't work. The mouse works fine, it's just the scrolling.