Multiple files corrupt

I’ve created some documents on a Netbook running Linux Mint and LibreOffice 4.3. I transferred the documents to a flash drive and then across to my Windows 7 computer. I subsequently deleted the files on the netbook and they are no longer in the trash bin. Now a number of files (about 4 out of 20) will open up but just contain hundreds of pages of random characters.

The files will not unzip and LibreOffice doesn’t give me an option to repair.

Are there any alternative recovery methods?