You need to print and mail your return without the payment.
You were supposed to file form 5405 in the year you moved out. This is in addition to any capital gains forms you might have needed to file. When you sold moved out, you owed either immediate full repayment of the remaining credit, or partial repayment, or no repayment; from then on, you owed no further payments.
You need to file an amended return for 2015 that reports the sale of the home and calculates your repayment. There will be late fees and a late filing penalty of around 50% of the tax owed at this point. Don't let turbotax calculate the payment, wait for the IRS to bill you for the penalty because you can ask for an abatement of the penalty if this is the first time you owed a penalty. (The interest can't be abated.)
For 2016 and 2017, you owed no repayment. You can file amended returns to get your $250 or $500 payment back.
For 2018 you owe no repayment but the IRS thinks you do, so you will need to print and mail your return, since the IRS is blocking e-filing.
Abatement https://www.irs.gov/businesses/small-businesses-self-employed/penalty-relief-due-to-first-time-penal...
Amend https://ttlc.intuit.com/replies/3288565
