Rediff Shopping — wrong size

hi sir/mama. im gold velangani and i purchased slim and lift and from ur site and the size is too small and im nt able to use it.i m very disappointed and i paid 299 for product and 60 rs for shipping..total 389 rs...im would like to return you the product as it ids of no use to me...instead can i buy other item in its place or replace the size i need.., , please help me and reply me as early as possible.