First, you need to make sure that you are on the right track in connection with the lawsuit itself. Are you sure that you have a lawsuit for "embezzlement", or is it for "conversion". Second, you say that your motion to compel was denied for "illicit" reasons. What would those be? Without knowing the reasons why your motion to compel was denied, it is difficult to advise you regarding additional discovery. Finally, you could notice the deposition of the defendant and take his deposition. You would be sitting down face to face with the defendant and getting his story. That is discovery too.
THIS RESPONSE IS NOT LEGAL ADVICE. IT HAS BEEN PROVIDED FOR EDUCATION AND INFORMATION ONLY. Mr. Mann is licensed to practice in the State of California. There is no implied or actual attorney-client relationship arising from this educational exchange. Moreover, the facts provided by you were not sufficient to allow Mr. Mann to advise you specifically regarding what you should or should not do. You should speak with an attorney licensed in your state, to whom you have provided all the facts before you take steps that may impact your legal rights. Mr. Mann is under no obligation to answer subsequent emails or phone calls related to this matter, or to take any action whatsoever.
If you served discovery and did not get the response you wanted, and then your motion to compel was denied, you still have options. You can serve additional written discovery, just asking new and different questions. Try using the form interrogatories if you have not already (judicial council forms - available from the court's website).
If you don't have time to do written discovery, then set a deposition.
Discovery can be complicated. You would be wise to consult or even retain an attorney to help you with that, especially any depositions.
Without reviewing the pleadings, the discovery already propounded, the responses, and the motion to compel, it is not possible to advise you as to what to do. Possibilities include third-party subpoenas and depositions, but those are guesses at best. In a disaster scenario, you are going to have to subpoena materials for trial (or do a notice to produce), and go from there.
It appears, however, that whatever you are doing is not working. This strongly suggests to me that you are being "outlawyered." By this, I mean your lack of experience in the litigation process is costing you, and perhaps costing you dearly. You would be far from the first pro per litigant I have seen who has lost because he simply had not mastered the litigation process. I therefore strongly suggest you retain counsel on at least a limited representation basis to advise and assist you. Without it, you risk losing your case in its entirety.
I mean you no disrepect in saying this. Litigation and lawyering in general, however, is a skill. Just like playing tennis is much more than running around and hitting a ball over a net, litigation is much more than reading and writing and talking. Your money invested in an attorney will be money well spent on your case.
There are many lawyers on AVVO who provide services on a limited representation basis. I suggest that you invest some money in your case, retain one of us to review the materials in your case, and give you some frank advice as to your situation and your chances for success.