I need my money back checkers

On the 21st 9f August 2023 around 10 am in the morning

I placed an order on the app of nappies and I saw a discounted amount at checkout of 217 before delivery

Then when I proceeded to add more nappies that when I noticed a sale and I added

Then at checkout the total was summed up and included delivery it also showed I had saved a huge amount and I paid that amount successfully and recieved an invoice for my purchase .

On the 29th I then recieved an amount of R1500 on my account but when I withdrew it wasn't working

I then went to my bank and that when the statement reflects an amount of R2000 been taken by checkers and left my bank with a negative balance.

When I called on the 29th a consultant said the invoice I have doesn't show on your side but I have proof of payment and invoices.

The consultant further said that you the app had a system glitch and they apologize and promised to have the matter resolved

I waited on the call as she had said her supervisor is in a meeting to try and fix it for me but nothing after that .

I've been calling them and I've sent proof uut final thing they told me is to bring back the nappies whereas I don't live with my child and probably they've used some packs too.

And I still feel it's their fault not mine as I did everything accordingly

Please help me