Legal importance of bayanah

Can anyone please guid eme regarding legal importance of bayana?

If the seller did not transfer the house, or change his mind and did not even return your money then what options the buyer have?

Do court help?

Do court transfer?

I mean what is legal importance of bayanh and how you can use it later to get house of payment?

Please check my relevant reply which I posted as last post of the below thread.

http://www.zameen.com/forum/discussions/buying_property/a_fishy_situation__need_help_to_evaluate_option-13038-2.html