Can we sort this out?

I contacted Fedhealth about joining the scheme 01 Feb 2016 and completed the application process with a consultant over the phone. Apparently this did away with having to complete an application form. Nonetheless I was subsequently e-mailed an application form, which I completed and returned. Up until this point (as I recall), Fedhealth did not inform me either verbally or in writing and the application form is silent on the matter, that my request to join Fedhealth effective 01 Feb 2016 would not be possible. As far as I was concerned we were all set: join date 01 Feb 2016 and first payment 01 Mar 2016. When I received my membership letter it incorrectly noted that the registration date was 01 Mar 2016. The contribution payment date was correctly noted as 01 Mar 2016. Fedhealth inform me that despite this ambiguous mistake, Fedhealth's opinion must prevail and that the registration date will remain 01 Mar 2016 and the first payment date will be amended to 01 April 2016. This is unfair and not what I asked for. No one said anything to the contrary, the letter of membership is ambiguous and not what I requested,but Fedhealth opinion prevails. Can we sort this out?