You must have taxable compensation from working to make any IRA contribution. It is too late have a return of contribution. All you can do is remove the excess with a normal distribution.
You do realize don't you that you have to file a 5329 for 2016 and pay the 6% penalty that repeats every year that the excess is in the IRA. That means that you must also file a 5329 for 2017, 2018, 2019 and 2020 with the same 6% penalty for 2016 excess. You must doe the same thing for the 2017 excess staring in 2017.
Unless the excess is remove by Dec 31, 2021 they will have another 2021 6% penalty for each. You will need a 2021 1099-R showing the distribution of the excess.
You must report the excess for each year on the correct 5329 for for that tax year.
You can obtain the past years 5329 forms here:
https://apps.irs.gov/app/picklist/list/priorFormPublication.html
Enter "5329" in the find box.
**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**
