"Can't get through to antenatal"

I went to my GP and told her I was 8 weeks pregnant. She asked me which hospital I wanted to receive maternity care from and I chose St Thomas (as St Georges is in special measures, I was given a choice between St Thomas and Kings). I waited patiently over Christmas for notification of my booking appointment and my 12 week scan.  I was 11 weeks and so I called to find out about the appointment. The booking number went through to voicemail requesting I leave my name and number and someone would call me back. I left these. I then looked on the website and discovered a self referral form that it advised I completed. I did so and sent it to the email address quoted. I then received a bounce back saying the email was not valid. I called the number again. Again only voicemail. I looked around the website some more and found another email address. I sent the referral form. I have received no reply except an automated acknowledgement. Now I've still had no response. I rang the booking number again. This time it said that the voicemail was full so I couldn't leave a message. I tried the general number for the antenatal clinic and that just rang out. I am in my late 40s and this is my first pregnancy, so I imagine I would be categorised as relatively high risk, so I would like to know that I am in the system and will be able to get the necessary scans and screening tests.