Dr. Brown's nipples

I'm so disappointed with them. I've had to go out multiple times now and buy new nipples because they start to leak wayyy too fast that my six week old daughter starts to choke because of how fast it's coming out. I know it's not just me because it also happened to my aunt when she used Dr. Browns. (No, they were not boiled in water, they've always been washed with hot water and soap with a nipple brush! We also don't poke through the nipple which I assumed could have been happening when my boyfriend cleaned them but he clearly said "No, you told me never to do that" lol)