If H1b petition expired without travel,employer never shared Receipt No?

I had H1b petition filed and approved by employer A, but expired without travel,Employer A never shared Receipt No. Am I eligible for H1b Cap Exempt from different Employer B

Yes, But you need a receipt number. can try FOIA to get that. do some research on it

I have heard of FOIA but never heard of confirmed reports of securing the receipt number and petition