It certainly can take time for an EBF baby to get used to the bottle. Perhaps you can ease her into it by expressing some BM, and then feeding that to her in the bottle. Then, when she catches on, start adding formula to it so that you have a mixture of BM and formula, then eventually, all formula.
Try and use a bottle that closely resembes the breast as possible (debate on what that is is a whole other topic. You may want to do a search on "best bottles", but the ones I always see mentioned on here are Avent, Dr. Brown's and Tommy Tipee). Start out using a slow flow/standard newborn nipple.
And, don't try and force it. You can't get them to eat when they don't want to in my experience. Good luck!
