That clamp just floats in there, it is not stationary or solid. I never even check mine when I put it in, never even thought about it. Now, I had the same blade breaking problem when I first got my Hegner. I purchased it from Advance Machinery. I contacted them and they worked with me. We had several conversations, I still could not get it to work on the small blades. I use 2/0 FD blades. They said they would work with me until it was doing exactly what I wanted it to do, but, I finally gave up and decided it only worked with bigger blades, and I could not do delicate pictures with it. I use my other saw for that. Then one day, after several months, I thought, no I paid a lot of money for the saw, and it had to work for me. I put a 2/0 blade in to try again, and it worked like a charm and has ever since. I do not know what I did different except maybe got the tension adjusted correctly, and the top clamp sorta floats also, in that the screw the you screw down to the clamp should not hold it tight there should be a sight amount of wobble. Rereading the instructions it states that also. Now I don't know if either of those items "fixed" my problem, but what ever it was, I am a very happy camper. I love the Hegner. My other saw is an Excalibur, a great saw, but if I had to chose I would chose the Hegner.
You might email or call Advance Machinery and discuss it with them. They we very good with me. I have no complaints with them. I gave up before they did.. https://www.advmachinery.com/collections/types?q=Scroll%20Saws
I looked, they do not list that model, so I'm thinking you may not be in the U.S.? So maybe you could still email them, or contact the place you purchased it from, they may give just as good service.