Should I cool-off?

I signed the contract in Vic. for H/L package fixed price on Tuesday 6th Oct. they( Agent and Vendor) demanded 10% deposit quick payment (because the "other party" was interested to buy as well and they paid in 500 holding deposit on Sunday 4th and were organizing a finance. I smell a rat in here... After I paid the deposit, agent send me a contract again to initial the change in the contract. Builder name disappears as vendor and is replaced by Jane Smith bla bla bla. (daughter of Builder company manager) I found out today... Her name is on the LOTitle certificate. Instead having one contract for sale of block of land (Jane) and building contract by XXX PTY LTD they are doing it the other way around, and I am very suspicious why? Conveyancer tells me today there is no building permit issued yet and who knows what name is there. I am thinking about cooling--off. well.... will loose 0.2% of purchasing price. Something is not right here. What do you guys think?
If they're asking you to change the contract, surely you can walk away with no charge, if you haven't accepted the change yet?
I can't see why you would lose anything by walking away.
If it doesn't "feel" right,now, then it's unlikely to get any better.
Go with your instincts!
Unfortunately I initialed this change..silly me. I terminated the contract yesterday and now will surely pay 0.2% out of purchasing price which is about $750 :mad:. I am now thinking if this contract was legally binding....just speculating at this stage.
When I first signed it on the 6th Oct. In the Contract the Vendor is listed as XXX Homes, however the Section 32 is in the name of Jane XXX(builder daughter). Is this legal? The next day they altered the contract and put Jane everywhere and emailed this change to me at 9.20 AM At that time I was in the bank and transfer the deposit at 9.50 without knowing about any changes to it. I read their email after I returned home about 10AM and later initialed the changes. So if they made the changes to it on 7th was the contract valid before I initial the change in it?