Bad in store service and product knowledge

Very underwhelming service from Karabo. I needed a prepaid sim, she was stern and seemed angry from the onset while assisting me...to the point I enquired if shes okay and if i did something to offend her, I even apologized if had somehow offended her. She then had a friendlier composure and said no its not me and shes not angry. Anyway, she sold me the wrong prepaid sim, said I need to be on the same plan to transfer airtime/ data (which the Cell C call centre said is not true), said there would be airtime on thr sim which there was none. When i got home and realised this, I called the store, she then changed the tarrif plan remotely without informing me and pretended to have sold me the correct sim. I did not even know that could be done, she could've just informed, now thats bad customer service and seems like it's withholding information from the customer! I had to call Cell C call centre where I was advised of the tarrifs and cost implications of changing it, as well as basically being told I was sold the wrong sim but the tarrif plan can be changed. Bad service instore, great service from call centre.