Terrible service

RCS did an unauthorised enquiry on my credit profile which has since affected my credit score. I've been calling and emailing them but no luck. Im in the process of applying for a home loan and upon me calling RCS was advised by Transunion to contact them to remove it which i did. I've worked so long and hard on getting my score to the level it wasand rcs refuse to assist in removing the note on my profile after sending them the evidence. I'm frustrated to be honest and i've communicated telephonically followed by formal communication from the 01 April and to date nothing.