Macbook pro retina (late 2013) mouse has stopped working

Hi,

The mouse on my trackpad has mysteriously stopped working today. The trackpad is fine but when I press the mouse there is resistance underneath it. I have contacted three Apple approved partners today who have all said that the battery has expanded meaning that several parts will now need to be replaced (battery, trackpad and keyboard). Each person I spoke with informed the repair will cost £400.00.

Not only does this seem excessive, is there not a simpler way to fix this without replacing all these components? I am astonished that the macbook requires such an expensive repair only two years into its life?

Any advice on to how to fix a mouse button for less than £400.00 (that doesn't involve relying on an external mouse) would be greatly appreciated.

Thanks