BS service

I have never in my entire life of being a consumer been so disgusted and rather concerned as to how this establishment has managed to remain opened for so long when they provide such BS service I’ve been to 3 different stores and I have wasted petrol and my time .however this is a lesson to me never to go back to this establishment , I partner bought our son 3 items and out of the 3 only one fits our son , the slip that I have only has one item on it and the second one still has the tags and everything as you would find it in the store all I wanted was for them to exchange the 2 items for bigger sizes , I didn’t want a refund or cash back I was sent to a different store and told that they had the sizes I need. I went only for them to tell me that they cannot exchange the other item since it doesn't show on the slip my question is why was I not told that at shop number 1 , then again the item is still as you would find it in store tags are there and everything I simply took a look at it and I said this is too small he didn’t even fit the item , so other retail stores are able to exchange without a slip or tags on the item but not earth child and why was I not advised on that from the get go .I regret wanting to support this establishment never again , I will ensure that none of the people in my circle ever buy from here sies