Bad attitude from the stuff and lack of knowledge

I went to pick n pay at diploid square and found that they had a promotion on Miller 12 for R92, and I found it not there but they still were displaying the advert saying they had it. I asked for some explanation regarding this and was treated bad and was given bad attitude by the assistant store manager by the name Isaac and the store manager didn't help also they all have bad attitude and don't know how to talk to customers