If you need to use a bottle then you just need to be persitant and try alongside with foods maybe even put some I his food

Get bub used to it during the day for small feeds, eventually he/ she will realise the milk comes easier through a bottle

Perhaps you could try putting some breastmilk in a bottle so that the taste and smell are the same and persuade gradually to take whatever from the bottle.. even a few drops on the bottle nipple might help the transition.

It will take a while. I would suggest offering small amounts regularly through out the day. Bub will get used to it