You must amend your 2016 tax return to report the excess contribution and pay the 6%, $330 excess contribution penalty for 2016.
For 2017, you'll either need to be able to apply the excess as an eligible Roth IRA contribution for 2017 or again pay a 6%, $330 penalty for 2017. If you were eligible to make a Roth IRA contribution for 2017 but already made a separate contribution to a traditional or Roth IRA for 2017, you can obtain a return of contribution of the separate contribution to allow room to apply the excess as a 2017 contribution.
If after possibly applying any of the excess as a contribution for 2017 any of the excess is carried into 2018, you'll have to do the same for 2018 or obtain a regular distribution of the excess carried into 2018 to avoid another 6% penalty for 2018.
[Edited to change the excess contribution penalty to the correct amount of 6%, not 10%.]
