Bad customer service

Spar -Stoneridge - Greenstone - I am very happy shopping here, its a clean and well run SPAR. However on 2 x separate occasions, - today 21-5-19 - being the second, - I have taken my Soda Stream for a refill and simply told they do not have #60 in stock without even checking (Grace being the attendant). I insisted she check her stocks as I know where they are kept, and indeed there was a full sealed Soda Stream #60 in stock. Relevant person should be better trained and told to put more effort in helping customers.