Lost receipt and shoe city doesnt want to return the item without a receipt

Yesterday i went to shoe city N1 to return my shoes i explained to them that i dont got the slip and i didnt get a slip when i went to collect the laybe the guy told me that i must collect my slip on a later day when i ask them yesterday where is my slip they told me that i cant get a slip because i dont got the first slip of the laybye.. I was very upset because i told them there must be a record because how would that guy give my laybye without a slip.