Shengen countries, and traffic tickets

I have written about this before, but from a different perspective. I am writing this time because I recently saw on an episode of "To Catch a Smuggler" (National Geographic channel)I that an arriving American passenger at the Rome airport was denied entrance into Italy, where he was to go on a cruise with his wife because of something he had done in France when he was in the military in his 20s. The man appeared to be at least 60. What the man had done was not divulged.
I'm wondering if anyone has any experience they can share regarding having an unresolved traffic ticket in one Shengen country ticket and being able to enter another Shengen country before that ticket is paid or resolved. Specifically, we inadvertently drove into a non traffic zone in a town in Italy in September 2023. Since then, it has been a long, frustrating process of inconclusive communication with the traffic authority in Ostuni., where it happened. The most recent communication was my husband's 2nd response to a registered letter from Ostuni about payment in which he asked for clarification as to how they wanted payment to be sent ( bank transfer, other) This was back in June 12 of this year. He had previously written with the same questions on May 28, without getting any response. To date, there has been no response from Ostuni. I am concerned about this because we have an expensive cruise booked out of Barcelona in early November. I would not want one of us to be denied entrance into Spain (a Shengen country) because of an outstanding traffic ticket. Is there anything we can do in the month we have before our flight to Barcelona to ensure there will be no problem. Thank you in advance for your feedback