You need to go back and file an amended 2016 return that includes form 5405 to report the sale. If it really was a short sale, then you may owe no further repayment of the credit. Or, you could owe partial or full repayment depending on the circumstances. After that, you owed no further repayments, so the payments you made for 2017 and 2018 were unnecessary. You can try including them in the total payments that you’ve made when you fill out the form 5405 on the amended 2016 return so you get credit for them. For 2019, you do not owe repayment, but you will be blocked from e-filing if you don’t include it, so you will need to print your return and file by mail. The amended return will also have to be filed by mail and it may take a long time to get processed due to the usual delays of amended return processing plus the coronavirus.
