Welcome back, bruce6!
It's great to see you again and I can see how making sure these sorts of details are logged properly is important for managing your business. Reading your question, I can interpret it a couple of ways, so I think some clarifying is in order to make sure we're on the same page and you're receiving the correct steps. I'll go over what I think you might be looking for and guide you to further assistance should you need it.
The first thing your question might mean is that your bookkeeper failed to enter any transactions using the HST code since November 2018. Hopefully that's not the case, but if so, there are a few options. One would be to import the transactions you can and manually enter those you can't. For instance, you can import invoices in bulk and import bills, but you can't import sales receipts, expense transactions, or bill payments.
The second thing your question might mean is your bookkeeper didn't record the sales tax filings since 2018. If that's the case, it means starting to file from that date. You can use our File sales tax article to help. While following these steps, keep in mind to make sure you're selecting the correct dates for the filing period as well as any payments.
If you're not seeing the filing period you want right away on the sales tax window, don't worry, you can still enter that data. Simply click Prepare return on a filing option you are seeing, then manually change the dates on the window that comes up to the ones you need. If you're not seeing the ability to change the Start date to what you need, that means sales tax has already been filed in QuickBooks after the date you're looking to enter. The filings would need to be undone in order to be able to enter anything prior to that.
An accountant user on your QuickBooks would be able to do this for you, or a member of the QuickBooks tech support team can as well. Choose from one of the options below to get in touch with support.
Phone and Chat: Click Contact Us to learn how to reach phone and chat support.
Schedule a Callback: click (?)Help in the upper right > click Contact Us > explain your situation > click Let's Talk > choose Get a callback (Note: Callback hours are the same as regular phone hours.)
I hope that helps! Feel free to stop by again next time you have questions. :)