Teach your staff customer service

I am currently renovating my whole house and I am buying alot of goods from your store I was there last week to return a product and I was next in the queue but this other guy was there before me at the counter he went to go fetch other goods so we said it's fine he can go and finish. We came today to return other products and Suzan at your return counter said go get the other things you need and come back to me. When we came back there was no one at the counter in front of her and we go to her she says no we must wait in the queue again behind 5 people before she helps us. I called for the manager who was very remorseful but Suzan even gave the manager attitude infront of us. I don't know if it was because the gentleman last week was white or the person she wanted to help first was African and I'm not. But I can assure you I will not be coming to your store again.