Employees blatantly uninformed about stock levels

I live in Gauteng but I am from PMB and visited in the weekend. My mom lives in PMB and we visited MTN (shop 211) in Liberty Mall on 31/01 to upgrade my phone. The contract is in my mother's name - we could renew our contract and were due for an upgrade. We were served by Sandhani. I could not make up my mind if I wanted the Blackberry 9370 and asked for a few hours to decide. We came back to the store after an hour and were puzzled when she said she was out of stock because she could have told us this before when we initially went to the store. How can staff not know current stock levels? We asked if the other MTN store (shop 124) would have stock and she said we could go check. It was almost closing time and we had to rush to that store. We were served by Ronelle Sewpersad there who was also clueless about stock levels. She said she would call us the next day at 8am to advise on stock levels so I could pick it up before I went back to JHB. She smsed at 9am when she knew i was leaving PMB at 10am. We still went to MTN shop 124 and were treated very rudely. She did not tell us to bring an ID and we had to fill forms. We decided to leave as i was rushing to go to JHB. Unacceptable.