Can't access mental health services

Hello everyone, I am new here and I'm not sure how to help myself anymore...

I am having a very difficult time coping at work and where I live at the moment. I finally asked my GP for help and he referred me to the local mental health team and a counselling place. This really helped me feel like things could get better as I've been feeling trapped and isolated.

Unfortunately I had forgotten that before being diagnosed with autism, I had received a diagnosis of Borderline Personality Disorder, and this meant the referral was automatically rejected without them having to see me. I had thought that my autism diagnosis replaced the personality disorder, as it's a diagnosis I always felt was incorrect anyway, but it seems that not only has it stuck but it means I can't get the support I desperately need right now. It feels unfair because its been a few years since it all happened and I've always maintained that the personality disorder was wrong. I have been shown how I meet the criteria for aspergers, but nobody has ever been able to tell me how I meet the criteria for bpd. It's made me more depressed and more withdrawn and I'm stuck.

Does anybody know whether it's possible for the GP to review/change an incorrect diagnosis, or is this just the way it will have to be? I'm not sure how else I can get mental health support as I can't afford private counselling!

Thank you and sorry this post is long!