Leaking bottles

I am deeply disappointed by Tommie tippee and I cannot let this go because the set I bought is very expensive. Months ago before I gave birth I bought their bottles from BabyCity at the Pavillion mall as they were highly recommended and had good reviews on tiktok and I am not happy with them. These bottles do not close properly causing them to leak on the sides, when closed you can see that it is not straight or clipping properly. Everytime when I am making a fresh bottle I need to at least try to close it a hundred times and sometimes I am successful and sometimes they leak. I would like to know the process of returning them as I have used them but I am disgusted by the results, my newborn is always wet, cause her to have a fungal reaction on her neck.