Zara canal walk

I bought a dress from Zara Canal Walk. The lady that assisted gave me a slip and placed it in the bag, not even 40 minutes later I checked in the bag for my slip and it was gone. I went back to Zara immediately to let them know what happened as it wasn't even a hour later. I asked could they assist with printing the slip again as the slip isnt in the bag. The women that is the manager didnt even want to assist she just looked at me and said there is nothing I can do I MUST keep the dress its not her problem. She didnt even want to help or try to make a plan. Im honestly so disgusted in the service and just because of that I will not be back. The manager that works there needs to go for training and learn how to speak to the customers too. I was calm and just asked if there was anything they could do but she didnt care to help. I think its quite strange as I have lost a slip before and they could print a slip for me. Honestly I would expect more from Zara.