Obtaining receipt number from ex-employer

My ex-employer petitioned for my H1B but didn’t provide me the receipt number or petition.

Now I want to retrieve the petition from ex-exployer and recapture the unused time of six years.

Is my ex-employer legally obliged to provide me the receipt number and the petition copy? Is it better to approach them through an attorney since I’ve a feeling they will ignore my request. What else can be done if the ex-employer declines to share the petition details?

They should share the application details but at the end of the day, H1B is an employer’s application and hence they may not budge easily.

I think requesting it should work if they are a big company.

If its a small company, then you may negotiate on what they really want in return for the details.

Are they not legally obliged to give me atleast the receipt number?