Baby bottle

Hi mummies! I'm a first time mum and my LO is 10 weeks old now. I alternate between latching on demand and bottle feeding EBM. My LO has been throwing a fuss with bottle and refuses to drink from it. The most she only takes about 20-30mls then stops drinking. I have tried getting hubby and my mum to feed with the bottle but baby still struggles to drink. I was using avent natural, avent anti-colic and now have switched to hegen bottle too. She was okay with the hegen bottle for the past few weeks.. till last week she started refusing this bottle too.. I also notice that she has alot of gas. I am returning to work next month and I need to source a suitable feeding bottle for her asap. Any suggestions for feeding bottles? How to know if a teat is slow flow, medium flow etc and how to assess which type of teat she will need? Thanks in advance for all your suggestions!! ?