What can be done on a credit lockdown?

Sure would help if you explain who you are and what you want to do. For example, if this is your credit and you want to release the lock down, you will need to contact each of the credit bureaus and ask for their special instructions.

Negotiate with the creditor. Almost nothing can force a lender to extend credit if they've decided not to do so. You might consider borrowing from friends and family to satisfy this debt-so long as credit facilities will be reopened.