Mr Price Home Slap threat

3 Weeks ago I went shopping at Woodmead Mr Price Home . I received a really bad experience that led to a sales assistant at the tills to threaten to slap me . I called head office after i requested her name and her colleagues were also afraid to tell me her name . Head office customer service called her and they also spoke to the store manager . She came to apologize and when i asked her why she said I cant take her back to the experience . The argument was about a discount voucher that she insisted i couldn't redeem as i was making a purchase when I started explaining to her she made an excuse of me on my phone earlier on and disturbing the flow of the Que . I was really shocked at the level of service and her shouting back at me. She stormed out of the tills and told me she will slap me. I have sent the head office an email after she didnt show any remorse when apologizing . I haven't received any response for Mr Price Home .