The bank does not receive direct notice of your bankruptcy filing. It is the responsibility of the creditor's attorney (or the creditor if not represented by an attorney) to direct the bank to release your account. You should make sure that the creditor and the creditor's attorney have been listed correctly in your bankruptcy schedules. It may be necessary to contact the attorney and remind them to release the account. Keep in mind that any amounts you have in the bank that exceed your exemption limits can be taken by the Chapter 7 trustee.
Because the creditor froze your bank account, it is the creditor who must contact the bank to release the bank account. Fax the creditor notice that you filed and to release the bank account. Have the creditor send you proof that they notified the bank to release the account. If the creditor refuses to release the account, they are in violation of the automatic stay and you could file a motion seeking sanctions against them.