Network doctors

On the 26th of August, I called medihelp to make sure the doctor I found listed on their website was indeed part of their network. I was reassured by the consultant that she was. I then made an appointment with the doctor which was 3 weeks later. Several appointments later, I get a notice from my doctor that my procedure will be out of pocket as they are not listed with Medihelp network. When I called medihelp, they stated that my doctor was removed from their network on the 30th August (only 4 days after I called them to double check) their response was that an sms was sent out to all their clients stating that there may be a change to doctors on the network from the 30th of August. I did not receive such a message. After many emails, medihelp will not assist me with these out of pocket expenses. I feel like this was extremely unfair as I did my due diligence by checking online and phoning them and I was at no point warned that the list of doctors may change.