Resigned Current H1B sponsor. They are now asking to return the documents. What is the impact

Currently I am working in company A (serving notice period) and will be joining company in next 2 weeks.

Next employer (Company B) does not want to transfer H1B.

Company A (My current company) wants me to return every single document related to H1B and also to pay the contract money (signed before applying for H1B).

Please advise if it is feasible to use the H1B in future if I could find an employer who is able to send to me US based on current H1B stamp on my passport.