Ex-employer used wrong SSN on taxes, insurance account and retirement

Ex-employer used the wrong SSN for my accounts in 2025 and caused multiple issues. While working there, I had insurance through the employer that had premiums taken out of my paycheck like usual, however I was never able to use said insurance for coverage because of the incorrect SSN. Even after reaching out to HR it was never corrected, likely due to the incorrect SSN on my record with the employer. A similar issue happened with the retirement account setup through the employer (elaborated on later).
I reached out after receiving my W-2 and 1095-c that had wrong SSN, and received a “corrected” W-2c (3 months after reporting the issue). But my 1095-c form that claimed I had health insurance the entire time I worked there was not addressed, and the W-2c only shows the corrected SSN, but no corrections were made to my wages or Social Security taxes withheld or anything else.
Regarding the retirement account, I had an account through the same company with my previous employer that was supposed to be merged with the retirement account created by the ex-employer that used the wrong SSN. However, when this happened my retirement accounts went from showing $600 (old account) and $0 (new account with wrong SSN), to only the new account with $3,000. I’m unsure if the wrong SSN being used linked to an existing retirement account for the actual person that the SSN belonged to (the SSN that was mistakenly used for me was my SSN increased by 1, which would likely be assigned to someone with the same birthday and within the same state as me).

I have no idea how to proceed with getting this fixed, as the ex-employer has refused to work with me beyond the W-2c, when I called the IRS they said that I needed the corrected W-2c and I would have to work with the employer regarding the insurance and retirement accounts.

Am I owed the money that was paid for insurance that I couldn’t use due to the wrong SSN? Is the 1095-c even valid? And if my retirement money that was taken out of my checks and/or additional funds from my employer toward my retirement account was put into an account for a completely different person, what happens? Does that change the amount withheld under Social Security wages? And the W-2c doesn’t show a corrected amount for Box 13 retirement plan. Is this mixup so bad that I need a lawyer?