I'm going through the same thing now. My 3 month old ds wouldn't take the bottle . He had the bottle once when he was 2 week's old and he was fine. Then I haven't worried about doing it again since . I've got a wedding next weekend and I want my mum to babysit so I've been expressing. I've done a couple of trial runs and he won't take it. Over a hour of screaming every time. I was using the Avent one which he didn't like. So I thought to try a different one just a supermarket one , he didn't take that one. I thought it's probably the teat so i bought a Nuk one with a wider teat rather then a skinny teat. He seems to take it better but he doesn't like it and it takes me over a hour to feed him because he mucks around chewing it. It normally only takes me to feed him 15mins by breast so it's very frustrating. But you just need to persist and I think the hungrier they are the more likely they'll drink it. Maybe try different types of teats to see what works for them and make sure it's the right flow teat for your bub goodluck