I contributed an excess amount to a Roth IRA this year (unknowingly) and do not want to pay the penalty. What do you recommend?

Contact your bank to withdraw the excess contribution plus earnings by the due date.

From the Publication 590-A:

To avoid the excess contributions tax:

• withdraw the excess contributions from your IRA by the due date of your individual income tax return (including extensions); and
• withdraw any income earned on the excess contribution.