front speaker problems

[Max9650]

Hi i got my starlet last weekend, and he said the front speakers don't work... the car didnt come with a headunit so when i got it fitted, we noticed that the 2 white wires going to the loom have been cut, and have fallen behind the dash :/

So whats the best option? Try finding them wires? Any tips on the best way to go about finding them?

And is there a reason why somone would cut the wires? There doesnt appear to have been any aftermarket sound systems in the car apart from the parcel shelf ones

Thanks all