Get onto your solicitor quick smart and let him know that you won't settle until the repairs are made good, or you have been reimbursed enough money to cover the repairs.
This advice is spot on .... and if they take too long .. get the solicitor to let them know you reserve the right to seek compensation as well. Get him to place a caveat on the title right away.
Do not settle until it is as it was when you inspected the property and made the offer.
good luck,
cheers
RightValue