New Member - Issues with import from Readerware

Hi, I am new to this platform after suddenly discovering that Readerware is no longer functioning. I have a database of over 2,500 books and am in the process of adding about 500 more that were recently gifted. I have the data files saved as backup (zip), CSV, and HTML including all available fields plus a few that I added. None of them pull all of my books into this database - it only pulled in about 1,900 of the total. Some of them are very old and have no ISBN or LC numbers. Is that why they didn't load? If I have to manually go through the entire list, that will be a freaking nightmare! It also looks like some of my fields did not import. I don't want to go any further with this if it doesn't pull in my entire list and all the fields.

Thank you for any assistance you can provide, even if it is to refer me to a different platform.