Pathcare wrong date claims

I went to the hospital in 2019 September, I use gems witch pays for hospitalization. So Pathcare ran blood samples on the day I was at the hospital and when they claimed they used a date I was not at the hospital and gems did not pay. I tried to liase with Pathcare to use the right date, sent emails and proof from the hospital that I was already out on the date they made claims. So they handed over my account without correcting their claim dates and I tried so many times to correct them. Went to Pathcare East London to solve the matter then the personnel who helped me sent an email to Pathcare to tell them what they did according to my information and gems and they said to her I refuse to cooperate therefore they won’t deal with the matter. So for them I have to pay for the matter to be resolved because they are not ready to send the right claim to gems. I don’t know what to do now because I have been sending emails with proof that I was not at the hospital on the date they made claims