Maternity cover is completely useless

According to the maternity guide that's sent from Gems when you register on the maternity programme the member is covered for 3 scans, 1 less than 12 weeks,one scan between 13-15 weeks and the third scan between 20-24 weeks, all three are clearly ticked in their maternity care guide however after those scans has been done,Gems refused to pay for the second scan.... the first excuse was the doctor used the wrong code when their book has the same code for the first 2 scans,second excuse is that the doctor has to write a motivation letter....upon refusing to do that the matter was being escalated, after more than 2 weeks of 'investigating" they call to say they are so sorry they can't pay and it was a misprint on that batch of books that was sent to members!