guys, thanks for all the info so far. my SPA date and booking date different quite a lot of days because we decided to add extra name last time but in the end can't do so as bank or lawyer (forget who) say must follow who is the one who that take the loan.

didn't hope can get the claims till booking date but at least can get the full amount based on the price of the house stated in the SnP. If they talk nicely that day, perhaps I will just accept what it is. The reply of "you should satisfy already since you got rebate" that me feel angry.

will update again once I submitted form to tribunal.