As per client requirement we have to to suppress an offer forever for a customer if the customer rejects that offer once ( if Pega receives 'Rejected' outcome for that customer) , how can this be implemented in Pega CDH? 

There is no mention of number of days in the requirement ( e.g. suppress the offer for that customer for x number of days). In NBAD under 'Constraints' tab if we define a suppression rule in contact policy library, we have to provide some number of days. That's why we are not able to define the suppression rule under contact policy library.  So what will be the best way to implement this?