Dissatisfied customer

So I visited Spar standerton on the 27th April 2024 at around 18:40 to get a few items. As I was about to pay there were 3 tills open and as I approached the lady in the middle till she put a closed sign and requested me to go an queue on the till, fine I went there waited for the lady in front of my to pay as she had many items. As I am waiting there comes a staff member paying from that lady that asked me to to join the other queue and a part of me understood because she's helping a staff member, guess what after the staff member a white lady was paying for her items at the very same till that I was requested not to pay from and she was not even asked any questions . Why are we not treating our customers the same? I am very much disappointed