I'm going through the exact same thing ATM!

She initially accepted a bottle. I had some EBM and once that was gone, I ended up getting formula for her because she was dehydrated and she took to it with great gusto. Now a week later she refuses to drink anything from a bottle. The formula is wasted in the cupboard it seems and she will only drink water from her sippy cup. She refuses to BF now at all during the day and will have a little go in the morning

I'm a tad sad but we've had a wonderful 12 months of it and after 2 weeks or so of continuous breast refusal I have given up wrestling with her.

If you want to keep persisting and try to ride it out, he might come good. I know it has worked for others but for me it hasn't.