Ok, I'll try to summarise the last several months of my experience in a few paragraphs.
I've been at my company for a little over 18 months. At first I entered as a junior developer, since I only had 2 years experience. After around 6 months, my line-manager (call him Steve), offered me a senior position, as they had interviewed many people for it and had not filled it. I told him I would accept as long as he promised to train me up, as I felt I was not suitably qualified at the time. Until this point, myself, Steve and a couple of the others were all friends, having a good time at work and doing social things outside the office.
Then everything changed. I don't know why, but I think Steve regretted giving me the position. He began speaking to me in unacceptable ways, i.e. swearing, barking orders at me and criticising everything I did, often verging on basically calling me stupid. The training he provided was basically writing code in front of me really fast. I didn't pick much up this way, but could tell he was trying to teach, so felt bad to say anything.
I kept a log of all of this and eventually, after 6 months of it, went to HR. I made a formal complaint about him and submitted details of exactly what he had said to me with times and dates and even a couple of witness' within the team.
HR investigated the case for several weeks, (during which time I had no work, as they said I could not work with Steve during the investigation, so I had nothing to do for 10 weeks, but still getting paid).
The outcome is that HR are doing nothing and that none of my claims can be upheld. Basically, he lied about everything, saying he didn't speak to me like that and shockingly, my colleagues lied for him as well, saying they never heard anything.
So now I'm in a position where I have no work, and he is refusing to accept meeting invites from me now the investigation is over to try and get some work and basically just move forward.
How can I salvage/repair this situation and co-worker relationship?
Before anyone suggests it, yes my line-manager has a manager of his own, unfortunately they are very good friends outside of work, so I've tried that route with no success.