Ordering my size dress was not acceptable and bad customer service

I went to Mr Price Port Shepstone today to exchange an item already having the item I wanted to get in mind. When I got there I found the dress I wanted to purchase but unfortunately they did not have my size so I politely took the dress to a colored lady who was on the floor who I assumed was the manager to ask her if my size could be ordered for me before I got into the long line to be told otherwise but i knew it wouldn't be a problem as alot of stores offer this service. I asked the question and her attitude to me was very mellow and uninterested towards my query and she responded by asking me "order it from where" so I said from another Mr Price store (as if it wasn't obvious where else would I expect you to order a dress from your store from?) And she then went on to tell me that they advise their customers to order an item online because if they order it in the store it costs the company alot of money especially if it is just one item. This response was it for me and I just said okay thank you and walked of to put the dress that was not my size back, I felt like I was gonna need to beg her to order my size and left me to question the fact then as to why Mr Price do you offer the service if the people that work in your store don't want to go ahead with the action. The dress was R200 that's money at the end of the day but apparently wasn't enough to order my size in, also I shop at your store every month and so does my family I'm pretty sure the cost to order something at a store can be easily covered. Worst customer service overall and I'm really disappointed by the attitude and absolutely no help from the lady I spoke to. Do you tell all your customers you can't order their size and they should do it online themselves because it costs your store money to order? Also just a straight no or yes would have been better not your questions to me the customer that you should already know