Unexpected Repair Cost Dispute

So, my father had given a service to a business in hopes to repair his tractor. When he was given the estimates, in person, the employees had informed him that the total costs were going to be anywhere from $*-*,* max. My father, given that impression, was fine with it, and had let them begin their services. However, a couple days have passed, and the business calls my father that the tractor of his chair was broken, and it was going to be an additional $*. Again, my father was fine with the charges, as he was given the assumption that the overall costs of service was going to be $*,* at most. But, a couple more days have past, and the business informs my father that the repairs are going to be a lot more expensive than what my father had thought, but the new estimate was never disclosed. Now, the business has my family's tractor in their possession, and won't give it back until we pay them $12k in services, but the $12k was never disclosed until at the very last minute. Does my family have any grounds against this business to take them to court? And, if so, what is the terminology for wha this business did to my family called?