Safety issues with pressure cooker Tissolli

Bought a Tissolli stainless steel set of pots. It included a pressure cooker. The safety devices on the pot did not click in place. The pot was exchanged, which took 2 months, but new pot had same problem. Lid is loose on pot and safety measures doesn't work. I am greatly concerned about the defect, as people can be injured or badly burned. No reply on emails from the manufacturer.