Slugs and snails just love this plant so could be either are the culprits. Slug pellets would be my answer or sharp grit on the surface of the soil. You could also look under the pot or scrape away the surface of they soil in case they are hiding there.

Yes, they often lurk under the pots until dark, or just inside the pots at the drainage holes. I'd use a few pellets in the pot if I were you as they are clearly lurking in or around it. But don't let your pets get at them. I find coffee grinds are quite good at keeping them out, but if they are already in the plant leaves this won't help.

Thank you very much for your good advice friends. Hope you get this message.

We do get the messages Renate. We get an alert whenever someone posts after us. You are very welcome. :)

All of the above or/and copper tape around the pot. Won't help if they are already in the soil. Doesn't do lasting harm to the little creature, just a little shock.