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I flew to the US on a business trip last month, and locked my soft suitcase with a TSA lock. I did the same on the flight back, but when I got my bag off the carousel at Heathrow there was no lock, no note, and a carrier bag containing a bottle of Hershey's sauce was at the top of the bag instead of in the middle where I packed it. Nothing else was moved, and due to the lack of a note I don't actually know who opened my bag or why.
I know it's not a big deal, but the lock was borrowed and I now owe somebody a lock. My colleague's suitcase was also opened but the lock was inside along with a note from the TSA saying that they searched the bag.
What can I do?