Hi, you can change the controls in the Raft Configuration window that appears right before you launch the game. Otherwise you can just re-download the game and it will be back to normal.
I am on mac, and I have redownloaded twice, but still can't change my left click to left click. Only buttons on my keyboard work. I think the configuration settings must have been saved somewhere on my laptop, but I have no clue where. A reset to default controls or something would be very useful.