Do i have a legal case?

I filed for chapter 7 bankruptcy in California. Once a school loan lender got notice of my bankruptcy they took my name off the loan and took it out from under my ssn. I could no longer manage the loan. They proceeded after my cosigner. After my bankruptcy discharged I received a letter from this lender basically stateing that since my bankruptcy discharged my name is back on the loan as the primary responsible person for repayment. My bankruptcy lawyer said they can't do this without a new contract being signed.