PLASTIMO Fork Terminal for Rail Line

The product description lacks installation instructions for screwing the railing line!!!
After inquiring with SVB, however, I was very kindly explained how to prepare the railing line for screwing into the eye terminal.

Good product, fast shipping.

Good product, fast shipping.

Product is high quality and functional. Price is unfortunately very high for the rather simple part.

I actually really like this type of railing. It looks neat and is easy to adjust and install myself. However, I find it very annoying that no assembly instructions are included and can't be found either at Plastimo or here. Okay, it might be unnecessary since it's almost self-explanatory. Nevertheless, it would be more reassuring if the correct installation procedure were described for a safety-critical component.

Especially since, after two years, the cable in the terminal has a centimeter of play. Did I do something wrong? Do I need to tighten it regularly? Is the construction perhaps not as stable as it seems? That's the kind of information I would expect to find in instructions.