No Service Offered due to changing of shifts!

I went to the BP Service Station in Dobsonville several times around 6 in the morning and got disappointed by waiting without being attended to and eventually when a petrol attendant comes, they tell me that they are still changing shifts and they can't assist me. I have never experienced such at other petrol stations no matter what time I go. Can't they find another way of changing shifts without affecting us the customers? Now I have lost out on a lot of Avios points I could have collected everytime I was turned away! I am not impressed at all!