I'm a bit confused regarding suing the conveyancer. Which conveyancer, the vendors or the purchasers? How can the conveyancer possibly know that the purchaser had no intention of paying the deposit? Correct me if I'm wrong, the deposit money is paid directly to the REA by the purchaser not via the conveyancer.
Vendors conveyancer allowed the contract to go unconditional without payment of deposit. The contract should have been nullified when it was not paid and not allowed to drag onto many months of stuffing around.
Sounds like the conveyancer was just focused on getting their services fee than protecting the vendors interest.