I was made to feel very uncomfortable at the store by the employees

I arrived at Woolworths Sandton city around 11h15 , I was there to exchange school shoes that I bought online. I went to the security lady, and got the small receipt for the exchange, I then went straight to where the school shoes are. I searched for about 5 minutes for the correct size, I did not get it then I looked around for someone to assist me, from where I was standing there was no one, I then saw 2 ladies at the kids clothing section, I went straight to them and asked for assistance. From where I found her we moved towards the customer service to a monitor to check if the store has the size I am looking for, she checked and confirmed that there are 3 pairs of size 6 which was what I was looking for, we moved from that monitor heading towards the tills that are positioned at the kids section, while I was still following her , the lady said to me I am going to the store room I will be back, I turned and went to stand to the school shoes so that It is easy for her to find me.

The problem started when I was standing there, I stood there for about 10 minutes, playing games on my phone, at first I felt like someone was looking at me when I looked indeed someone was looking at me from the LEVIS section, it was a lady with short hair, wearing a black and white stripped jersey, when was pretending not to look at me when I looked eyes with her she made as though she was speaking to one of her colleagues busy poking her nose. After about 2 minutes a security guard walks towards me, I smiled at him and asked if they have sent him to check me out, he got embarrassed and said No, I tell him the reason I have been standing here for a while is because I am waiting for the lady that was assisting me, he politely said she will come back. After the guard passed, I think after 5 minutes 2 ladies pretended to be speaking about lunch times not far from where I was standing, but I could tell that they were both eyeing me, if all these people felt like I was there for a long time why did none of them approach me and ask if I have been assisted or not ?

I want them to tell me what is the turnaround time that I have as a customer before they start making you feel uncomfortable, how much time must I spend in the store before I am being followed around?

I was wearing a black jacket with blue jeans.