Mr price refused to refund my money

I was at the store on Friday, a lady that works there pulled me out of te que as I was about o pay and told me to go pay on he other side, they scanned all the items and I paid, then the till went off and didn't print a slip so they made me pay again for the same items, at this point I had paid over 2k for items that were only supposed to cost 1k,thry said they would refund my money, to date am still waiting the Custer service said I must go back to the store, at my own cost. So basically he store ****** me, they stole my money.