Bathroom faucet Similor Milor single-lever mixer: Lever loose - how to tighten?

Hello
I have a question about the single-lever mixer Similor Milor: the lever is loose. How can I tighten the lever again? Under the lever (handle) there is a black screw, made of plastic I assume. I loosened it a little, now the lever is even looser. But I can't get the screw out...
Is that just a "cover screw," and underneath is an Allen screw?

That shouldn't actually be that difficult, but I can't manage it... and I don't want to break anything...

Regards
Thomas

On their homepage, you cannot see the construction of the fitting. The best would be to inquire directly with the manufacturer.

Thank you. I have now looked at the operating instructions on the KWC homepage, there you can see that there are 2 screws on top of each other. An Allen key is noted for this. So the upper one must really be a cover screw. Maybe it’s just stuck, like the "Ewigen".

We had the same problem. We then called the company and they explained it to us. Under this [Deckschraube] is the actual screw. Tighten it slightly and then the lever is fixed again.

Exactly, and we have had these experiences as well. It was not clearly visible on the company's homepage. We then called the company there, and they explained everything to us in detail.

All very friendly. :)

I am now facing this problem and thank you very much for the thread. I also have such a single-lever mixer and cannot get the screw out. If I turn the other screw, everything becomes looser. So this seems to be a general problem. I will call the company there.