Hello AnastasiaTkachu
You can find our English-speaking SBB community here: SBB Community
Provided you lost it on one of the SBB trains, or on a train whose operator uses the SBB Lost & Found service, you will receive two updates, one after four and another after ten days. The registration of the found items may take time; consequently, you have to be patient.
More information on the Lost & Found service you can find in the respective FAQ’s: Questions and answers on the SBB Lost and Found Office | SBB help & contact
Kind regards,
Roland