If you're very handy soldering, you can replace the chip on the board. I only recommend this if you have a deft hand and lean wallet (otherwise you're better buying a new board. I would not even bother if you're using a pololu board just get a new one. The chip itself is like $4.50 and the board is $10)
But i have replaced the DRV8825 chips a couple times before. The key is to load a ton of solder on the pins on one side to get a good thermal mass, lift that side with a xacto knife while you're running the iron up and down the length. The second half is easier to remove for evident reasons. Now you want to solder-wick up the remaining solder, apply flux to the pins, and place your new chip onto the board. The best technique for these mofos is to tack the corner pins with big globs (small as you can, but they will be too big), then drag-solder. The surface tension will wick solder to each of the well-fluxed pins as you drag a soldering iron with some solder on it across the pins. If you ever feel things are heating up too much just give it another shot after it cools and reapply flux.
Total shit that they gave you bad cables though, it's a bad sign to not have your crimping art down 100%, because bad crimps are a future mechanical stress failure, whether they were tightened too much or nicked too badly.
I haven't had trouble with the stepper-motor cables (those come from the stepper motor factory), but I would be cautious about replacement cables for any other part of the system from pololu. Esp parts that move a lot, i would get high quality silicone wires from hobbyking or some other hobby-shop. The wire that my solidoodle came with was very low quality and eventually fatigued from the printer head movement.
