It would probably take a lawyer to get anything out of this. If I were you I might have a consultation with a lawyer and see what they think of the situation. Do the plumbers know what you'd have to do to get this problem fixed permanently? http://www.watsonsplumbing.com/plumbing-well-pumps-service/2105299... more
If the seller did not know of the problem beforehand, and there was an inspection done that said everything in the house was fine, then it's not their responsibility. I would recommend talking to them about it in a calm manner, and coming to the best agreement. Plumbing problems are not fun to deal with, but it might not be their fault.