Unprofessional staff at engen onestop langebaan

On numerous occasions i have been trying to pay for items bought at engen onestop langebaan on the R27, using the snapscan application. On this occasion engen onestop personnel as always insisted that the snapscan facility doesnt work. I was adament that they try because i know it works. They then procedure to put the snapscan payment through and it was successful. The conduct where personnel blatantly lie to customers because they are unsure or dont know to me is viewed as highly unprofessional and not acceptable