I have a contractor who has drug his feet on a home improvement job. He continued to change the date of completion. He has been paid half so far. We now want to be finished with him. We had to hire someone to finish some drywall and ceiling work. The total due for completion was $17,510. He wanted 90%, $15,500, and then the rest of the money when he came back to finish. We proposed to pay $15,000 (minus $500 for drywall/ceiling). Are we responsible to pay for work that is not complete if we don't have him come back?
Cases such as yours are almost always very dependent on both the contract and the facts. The language of the contract is important, as that language will dictate whether the contractor is in breach of the contract. If the contractor is in breach, then you can most likely terminate the contract, hire someone else to finish the job, and even go after the original contractor for excess costs.
That all being said, the original contractor may be upset, and may file a mechanic's lien. Because of this, you should have an attorney look over the contract to offer advice on the strength of any breach of contract claim/defense you may have. In short, you want to get your ducks in a row before engaging in any action such as terminating your contractor and/or hiring a subsequent contractor.
Without a contract, there is simply no way to answer as to your obligations without a review of all of the facts. Any written communications are extremely important, such as communications related to cost or the time for completion of the project. Those communications can form a contract. However, without strong written communications the case will likely become a he said/she said type case where it is difficult to determine your true obligations. Sorry I am not be able to offer you a clearer picture, but that is sometimes how these things shake out.