A. Dear Mr. and Mrs. Burt,
I have not seen the contract you have signed, and therefore I am not sure of the type of agreement you have reached on the documents. A private purchase contract can allow any of the parties to pull out of the deal, envisaging penalties for it. The most common one provides that if the buyer pulls out, he will lose the deposit paid, and if the vendor does, he will have to refund double that amount. This has to be specified on the contract.
However, it may be the case that the private agreement has been arranged in a way that no party can opt out without the other party´s consent. Both buyer and seller in this case are in a position to, if any of them breaches, to sue for performance and damages, as the case may be. In this case costs would most possibly be imposed on the losing party, that is, the party who decides not to continue with the sale.
As far as how long would the court case take, that depends on the district court where your property is located, although you can be sure that in first instance the case is not likely to be decided before 8 months at least.
I suggest you seek advice from your lawyer as to the options you have available.