Bad service

I went to the engen garage in Parktown to buy pies at corner bakery, when I got there the lady that was supposed to be serving me never gave me time to offer service and then came another customer who she served, I then took the paper from the desk where she was supposed to be helping me to go pay, not realizing that I took wrong, when I got back to her asking for assistance, she was rude to me telling me that I shouldn't have taken those papers as she won't be able to exchange them for me, I then requesting to speak to her manager who also took her own time, while waiting for the manager, the very same lady who was giving me attitude, said in her own exact word's, and I quote "phela angi lali lana mina, ngiyaphuma" (I don't sleep here, I'm gonna go out) which I take as a threat, eventually the manager came and resolved the matter.