Hello @sskdek
Thank you for reaching out on the community and telling us about your issue. I do apologize for the issue you're having. I'm wondering here it sounds like you may have gotten some duplicate transactions causing the issue you're having. To start off here the first thing we may want to attempt here is to restore a backup to a previous point where our register was correct. I'll leave steps on how to do so down below.
https://www.quicken.com/support/how-backup-or-restore-your-quicken-data
Once you've done this we'll want to try to try reconnecting the account again but we'll likely need to delete the duplicates. You should see on the left side all the new transactions will have a blue dot next to them. You should be able to click on the column header and it will sort the new transactions. Make sure not to delete any new transactions. Delete any of the transactions prior to the new ones including the new starting balance as well. I'll also leave steps on how to mass highlight down below.
Thanks,
Quicken Francisco