Yes, Quickbooks sometimes garbles data when importing or exporting - or really doing anything - it sometimes crashes, requiring a rebuild of the database tables.
When this happens, about 90% of the time running the Quickbooks Rebuild Data (File > Utilities > Rebuild Data option will make everything okay again, and no data will be lost. Make sure to check that all data is still there after running the Rebuild Data! If it doesn’t work or you have missing data, sometimes Quickbooks Support (or you) can fix it by downloading and running the Quickbooks File Doctor on the database file in question.
If this still doesn't work, the only option is to restore from backup. If you have a Quickbooks Server, we should have nightly backups of the Quickbooks database file, so long as someone hasn't moved the database file off the server for some reason or another.
Get the Quickbooks File Doctor here: