Assuming that your buyer's Realtor used CAR forms, the RPA has several contingencies. You state that there were "NO CONTINGENCIES". If that was true, that includes loan approval, property appraisal, physical inspection, Natural Hazard Disclosure, Earthquake Disclosure, LA City inspection, wood destroying pest inspection, etc. So there is no remaining contingency, expect the three day walk through. Assuming that you gave the buyer the aforementioned reports. Each time the buyer receives a new disclosure the three day recission period kicks in.
So aside from a 3% deposit, normally the buyer has to make an additional deposit to close. So AFTER ALL contingencies were removed, he did not want to or was unable to come up with the additional deposit. Those deposits can be either during escrow (say a week after contingencies are removed, so they become part of liquidated damages), or PRIOR to the close of escrow, which means they are NOT part of liquidated damages.
I am not your agent and do not know all the facts, however it appears to me that you might want to consider a couple of things:
Without knowing the facts and seeing the paperwork, in general the buyer has numerous options to "get out" of a transaction. The contracts are "buyer friendly".
You mention that you called escrow only to find out that it never opened and the check was never deposited. With a competent Realtor representing YOUR interests, coupled with effective escrow company, that "surprise" would not happen.
So, yes, see an attorney. Also, I read your profile and you are no doubt very good at investing in properties. Don't you think it would be to your benefit to have a competent Realtor represent you in your transactions. In most transactions I believe a Realtor MORE than earns their fee by saving their clients money, stress, disappointment, and avoiding legal entanglements.
It is wise to seek legal advise. It's worth a try, buyer can backed out but with reasonable cause like death of the spouse or bankruptcy and some other reasons that both of you might find reasonable.
I wish you all the best.