Breastfeeding challenges

My newborn is 12 days old and is refusing to breastfeed. He was initially taking expressed breast milk from a bottle, and now he seems to have developed a bottle preference.

Whenever I bring him to my breast, he closes his mouth and refuses to latch. I also have flat nipples, which may be making latching more difficult.

I really want to breastfeed and would appreciate any advice or success stories. Has anyone been in a similar situation and eventually been able to get their baby to latch and breastfeed successfully? What techniques helped you?