Employer wont hand over I-797 and even a copy

Hello Friends - Need a suggestion.
I am applying for AOS and this is regarding the “Evidence of continuously maintaining lawful status”. For this I am attaching all I-797 approval notice copies. I switched employer and my case involves EOS, COS. Entered through L1A, filed L1 extension timely and got it approved. While my L1 extension was pending, moved to a different employer on H1B and currently on H1B. L1 extension was approved exactly 15 days after I moved to new employer. I have the receipt number for the L1 extension, however do not have the I-797 approval notice. Checked with my previous employer and they wont release a copy of the L1 Extn approval notice and not send the original one too.

What options do I have? Opened FOIA request mentioning my L1 extension receipt number, no updates yet, after a week. Should I wait for FOIA or file I-485 with a copy of USCIS case status check tool. Your suggestions will be helpful.

@Kalpesh_Dalwadi any suggestion would be helpful. Thanks in advance.

You dont need to provide the L1 EOS approval as you already did change of employer and change of status. Also as L1/H1B are employer petitions I doubt USCIS will provide a copy. Just go ahead and file AOS with copy of all I-797 you have in your possession.

Thank you @Kalpesh_Dalwadi I will go ahead with filing AOS with notices that I have.