"Never able to contact midwives"

Throughout my pregnancy (I'm now 36 weeks) I've never been able to get hold of ante-natal or community midwives by phone. This has been very frustrating as I wanted to rebook a scan or cancel an appt. If I had a serious pregnancy issue or concern I'm not sure what I would do as you're meant to be able to get hold of your midwife between appts. When I do see the midwife for my fixed appt I'm happy with my care but it appears that there is little resource for any support outside of your standard ante-natal appts. I'm currently trying to change my next appt but as I can't get hold of anyone I will be a no show.