Originally Posted by SkyBound
I wouldn't. Especially since it was their screw up. If someone hit your truck you wouldn't try to fix it yourself with sheet metal and rivets. Their mistake = their fix. Get a quote from the dealer and go from there.
X2 -- There's no way to know if there's internal damage to the wiring where the cable was stretched or kinked when the lawnmower blades hit it. I'd replace the entire cable and sell the old one for scrap. Having a power cable go up in smoke wouldn't be much fun, especially at 3 o'clock in the morning.
When the mower hit it, it could have possibly yanked at the cable all the way to where it goes into the trailer, or to where it plugged in to the receptacle. Better safe than sorry.