Currently there isn't a way to undo a CSV upload. The best workaround that we can offer at this time is to sort your income and expense pages by the account "Other Transactions," and then to do a multiple delete. To do so, please refer to the following article:
NOTE: Deleted transactions cannot be recovered. If you are not sure if you should or should not delete transactions we suggest simply re-categorizing the transactions to "HIDE Duplicate/Wrong Income" or "HIDE Duplicate/Wrong Expense." Doing so will just hide the transaction from your business page until you know for sure that you want to delete that transaction.