Hello ,

You can go back and get back your certificates , just give a formal application letter in the office they will provide you the certificates

no nobody will dump it in trash those certificates has got value , dont be upset reach there as soon as possible and complete the procedure to get back the certificates back , once you have submitted the certificates in an institution then they are responsible for the documents and are directed to return it back when ever asked

hope this hepls you

best wishes for your future