Bad service

I have sent back my order because they keep sending the wrong product. My delivery is set for 9-10. The delivery came when I was taking my hubby to work. I was ask to select an alternative which I did and still the picker selected something I did not want. I have come to the store to get my money back and do my own shopping as I am so frustrated with this system. Store manager can't assist with the refund either and can't explain why system is telling the picker to pick the wrong stock.