How do I sue my contractor?

[Brie Schmidt]

For all you contractors / rehabbers - help me out here. We bought a house last June and hired a GC to do about $60k worth of work - the main thing being to replace all the cloth wiring in the house, as well as upgrade us to 220 and install new panels. Well yesterday the lights on our first floor went out so we contacted the electrician he subbed. today we are fixing the problem (loose wire) and come to find out he never rewired the existing outlets/lights - he was only contracted to do the new stuff. This is how he line item it from our contract. I will be getting a copy of the contract he had with the electrician, but how do I best go about resolving this?

Electrical

New 200 amp service with permit and new panel box $3,850.00

Additional for 3 panels $350

Estimate 40 openings for rewiring $55 each additional opening $2,200.00