Zara.com review: customer service

09.09.2019 I visited the store at Brompton road at 20:00pm.
I went there after work just to get the coat and I was quite happy because I find it very quick as I had very long day at work . However, I went to the till to pay and while I was paying I dropped little feet medallion (Gold pendant) with little stone on the side that I had in my wallet. I kept it in my wallet because my necklace broke and I did not want to lose it. However, I noticed that and I put the medallion ( pendant) back in my wallet. There was also used tissue and because I was in the rush I got confused and I asked the lady that was serving me if that tissue was mine as I was thinking if its mine would be so rude to leave it. She shocked me when she replied " NO the tissue is not yours and the medallion (pendant) that you took is not yours either, I think is previous client left".
It made me really upset as I had to explain myself, I do have a prove where I bought it. And it has very strong meaning as is holding memories of my baby that passed away.
The girl said that its ok I can take it if I think is mine! I don't think, I am sure it is!
I left the store with the tears in my eyes as the last thing what I want to explain such a painful and private thing to the sales assistant.
I work in customer service myself at Harrods, and I never heard that someone would be so unethical and treated as a burglar just because their drooped and picked up their personal belongings from the floor.