I bought something from Germany about 1 year ago, and when it was delivered there was an import tax of about 50 CHF, which I fully expected and planned to pay, but then forgot about.

6 months later I got a reminder from the Swiss Post that it remained unpaid. I was goig to pay it but now lost this letter Usually when I don't pay a bill in Switzerland they keep sending reminders every month with warnings and added fees. The Swiss Post sent one reminder in only 6 months,and now seems to have forgotten about it

Should I go to the Post office and ask them? Altho it's kind of hard for me to explain "I got a package a year ago and never paid import taxes, and I'd like to pay it now?" Throw in my bad German, and they'll really look at me like I'm some nut-job. What should I do? Wait for the next reminder to come in the mail (next year?). Or maybe they forgot about it, as I almost did?

The "nut-job" angle might be your "get out of jail" card.

Use it.

Me? I'd just roll up at the post office and tell them what happened. You'll be a name on a file somewhere...