If you have been served with a subpoena, you have a legal duty to produce the records that are in your care, custody or control. If you fail to produce them, you can suffer adverse consequences. You should do everything in your power to quickly get the records that are requested, or to request an extension of time to do so.
Good luck to you.
This answer should not be construed to create any attorney-client relationship. Such a relationship can be formed only through the mutual execution of an attorney-client agreement. The answer given is based on the extremely limited facts provided and the proper course of action might change significantly with the introduction of other facts. All who read this answer should not rely on the answer to govern their conduct. Please seek the advice of competent counsel after disclosing all facts to that attorney. This answer is intended for California residents only. The answering party is only licensed to practice in the State of California.
You should respect the subpoena power of the DLSE to the same extent that you expect a favorable determination by the DLSE will be binding upon your (former) employer.
This is an incomplete answer written in response to the limited facts provided. It is intended as a courtesy to better inform the reader about his or her possible rights and potential courses of action; it is not intended as formally researched legal advice or as an agreement to enter into an attorney-client relationship.
As to your not having phone records, if they are subpoenaing your cell phone records, most cell phone providers make your cell phone records available on-line. They can be printed out. If, however, they are absolutely unavailable to you, you should send a fax (followed by hard mail) a letter to the hearing officer assigned to your case (the name is on the hearing notice), with a copy to the attorney, objecting to the subpoena on the grounds that they are not in your custody, possession or control and equally available to the other side by subpoena to the phone company and that they are irrelevant to the hearing. The hearing officer will either continue the hearing to a later date or go through with the hearing to decide whether the records need to be produced before the hearing can be heard.
They say you get what you pay for, and this response is free, so take it for what it is worth. This is my opinion based on very limited information. My opinion should not be taken as legal advice. For true advice, we would require a confidential consultation where I would ask you questions and get your complete story. This is a public forum, so remember, nothing here is confidential. Nor am I your attorney. I do not know who you are and you have not hired me to provide any legal service. To do so would require us to meet and sign written retainer agreement. My responses are intended for general information only.