You can give a shot to Stellar Phoenix Mac Data Recovery https://www.stellarinfo.com/data-recover... software to scan your hard drive and locate all the deleted Office for Mac files. Hope you stopped copying any new data to the hard drive. You surely don't want to overwrite the existing deleted file information. By the way, you should have backed up your macOS with Time Machine. It's a complete free in-built Mac utility and there is no reason as to why you do not have the Time Machine backup on your Mac. Anyways, if some of your important PPT and MS Excel file gets deleted, and that is too from Trash folder, then you need to use a above mentioned data recovery app. I recommend you change the preference to only Document in your Mac system, so that this recovery software scans only .XLSX, .PPTX and .DOCX related files only. It will exclude all other file formats like JPEG, OPNG, GIF, MP4 etc. and takes less time in scanning.