Sorry you are feeling upset, you must be feeling very emotional and have lots of questions having reached out and hit this first hurdle.
A close relative went through social services a couple of years back to trace his family (was adopted at birth in the 1940's). The social worker involved spent two sessions speaking through all the potential reactions, emotions, and how to handle contact so I know it's different for you as it's not adoption but I think the company who traced your father are not very responsible if they haven't covered all that.
I'm sorry you haven't had the reaction you were hoping for, we were told very few many people do have a happy reunion, especially the longer time has gone passed since initial separation.
The social worker said that many people have kept previous children secret from their future families so don't want to rock the boat, and sadly she stressed that financial concerns and inheritance can cause issues (both the lost and seeking individuals can be vulnerable to exploitation), even if the initial reaction from the family member is positive.
We were told that often even if the parent responds positively their family may not and you should prepare yourself for all these options.
My relative decided not to pursue further contact once they had the details as they felt they could not handle what might be. Their sister similarly traced her birth family at the same time and she has had contact several times, including attending family events. But their lifestyles and financial circumstances are very different and some members of the family have been openly hostile as they feel they are looked down on by said relative and have nothing in common so refuse to speak.
So tread very very carefully as you stand to get very hurt. Could you seek counselling through your work or GP so you can talk through your experiences, whether or not your father responds. My relative was in his late 60's and was surprised by the emotions the whole experience uncovered (and they're a very traditional, normally unemotional individual) and was glad to have been guided through the process.
Don't try to force contact, and take care of yourself x