Just curious whom it concerns and who I should message about trying to customize items, but lagging out and said fraises were gone. It was only 20 fraises, but it's kind of upsetting to know if you try and customize or maybe even buy at the wrong time you are in risk of losing them.

The issue is that the server saves your stats, cheese, and et cetera upon a clean "shut down," in TFM's case closing the window. That's all.
You might have to send a contact (http://www.transformice.com/contact/) but I don't know if they'll refund.