Advice needed I’m Ending construction contract after cooling

I signed a contract for a house and land package and the contract is the 'Victorian Builders contract' the land has not been subdivided or titled yet and will not be doing so till January 2020 (if this is to believed) its still a farm.

We are well over the cooling off period but we keep hearing mixed messages about when the land will be titled and the vendor and the developers talk in riddles trying to get out of giving me a time frame, I'm getting cold feet and want to cancel the contract and buy a house that is already where it is supposed to be.

in the contract myself and my partner are classed as the "owners" or owners to be. Due to no land subdivision they have infringed no costs for this and they are holding 5% of the full house and land amount. I can not find anything in the contract that states what they can charge us if the contract is ended prior to any works happening
how much could the builders take off us for cancelling? They have seven months before the land is even titled to find another buyer.
Does anybody know what would be a reasonable amount to charge us for a breach of contract ? Has anyone been in this situation and what was the outcome ??