Truworths poor service at cosmetic

On 03 March 2021 I went to Witbank truworths Highveld mall I bought foundation brand is esteer Lauder which worth R655,the ladie who was testing me I told her that this colour is lighter she said is my colour and I should buy a dark powder to match so when I arrive at home I looked like I apply ash on my face I returned it on 4 March 2021 I told them the manager and the ladie who was helping me yesterday they said they can't take it back because Is already open there is nothing they can do,so I can't use it because is not my colour and is expensive they even gave me an attitude ,what to do? Please help