Dischem Sunninghill help desk does not wish to help

The staff was so rude at Dishchem sunninghill . The staff sitting at helpdesk counter does not wish to help. For my baby on purchase of 10 diapers 1 diaper is free I went to enquire if I am elligible for free diaper as I already have purchased many. The lady rudely says u ll get sms then come and does not want to check on card then and there . Is it a trap to engage customers to buy atleast 10 and then do not attend.