rude supervisor

I was totally embarrassed due to shopping with my husband card and the cashier told me I am unable to pay for my goods because the card had MR on it. She then called her supervisor who was totally rude and screaming at me during her explaining along with rolling her eyes she insisted I leave behind my goods if I don't have cash to pay for it .... this has not been the first time I even stopped shopping at phoenix plaza and shopped at Mt edgecombe due to embarrassment and it has happened again .... Monday night I shopped at Mt edgecombe and was allowed to use the card today been Wednesday embarrassed and shouted at while other customers came and witnessed this drama this lady is a thin tall with shoulder length hair I will never shop there again ...... NB : IT'S A JOINT CHEQUE ACCOUNT WITH MY SIGNATURE ON THE BACK OF MY CARD AND I ALSO PRODUCED MY I'D