You should withdraw the earnings related to the excess contribution. Your financial institution must be able to calculate that amount of earnings for you.

Since the calculation is very complex it is highly recommended you have the custodian calculate it.

Read what they said, again.

I asked, they said, I need talk with tax adviser, they can't tell me how to do it.

I suspect any custodian that will take your IRA money is required to do this if requested. There is a form to be submitted, called "Request for Removal of Excess Contribution"

call and ask for the form, or find it on their website.

I did summit the form provided by the financial institute. They returned my form said the withdraw amount is wrong, because I didn't include the gain. I call them for the right amount, how to calculate the gain I need to add to the withdraw amount, they didn't give me answer, just said I need talk with tax adviser.