Retirement tax questions

Thank you so much, I really appreciate it.

One more question please.  Who do I ask for the return of excess contribution?  I asked my employer and they said they would not return it as it was not their fault and they will not send an amended W-2. Would I go to my 401k plan/provider and ask them for a payout before April 15 (and would this be considered a distribution)?

Thank you

Aroon