Can anyone help me with a 401k over contribution issue? I am past the April 15th deadline and my employer isn't helping.

I had a contribution from my previous employer and my new employer 401k, which resulted in over contributing to my 401k.

I am not getting much clarity at all and have no idea what direction to go. This feels like a nightmare. I contacted HR with my employer and they directed me to call Fidelity and to contact Payroll via online ticket process. I called Fidelity and they told me to reach out to the employer to get a form to fill out a return for excess deferral, which was 2 days before the April 15th date. I took action and sent a form to Payroll (from a request ticket online - no way to call them), as well as filed an extension for my taxes. It's been a week later and Payroll from my employer wrote back finally. They told me they can no longer help me since I am past the deadline and that I would have to contact the IRS. I tried calling the IRS, but their automated telephone service tells me to look at their website which does not help with this issue.

How do I go about getting this corrected properly and completing my taxes? I tried contacting a tax assistant on TurboTax Live and they told me to get my money back from my employer, but I told them what my employer told me and they still insisted. This just makes me more confused.

I am not sure how to move forward with this issue? What are the penalties and what happens to the over contribution? Do I have to withdraw it immediately or how can I resolve this so I can complete my taxes properly? Please help!