Hi Alice, you have entered into a situation that is best reviewed by a Real Estate lawyer. Any Realtors responding to this question will only be able to provide opinions based on the presented information without knowing all the details.
I would suggest the exact details of the contract, Buyer/Seller circumstances, and other pertinent laws need to be considered by a lawyer if you are looking to obtain actionable advice regarding your situation.
Also, note you and the Seller likely initialed, and therefore agreed to, Para 17A&B of the CAR CA Residential Purchase Contract, which requires Arbitration and Mediation of disputes. However, there are some exclusions via 17B(2)iv:
(2) EXCLUSIONS FROM MEDIATION AND ARBITRATION: The following matters are excluded from mediation and arbitration: (i) a judicial or non-judicial foreclosure or other action or proceeding to enforce a deed of trust, mortgage or installment land sale contract as defined in California Civil Code Â§2985; (ii) an unlawful detainer action; (iii) the filing or enforcement of a mechanic's lien; and (iv) any matter that is within the jurisdiction of a probate, small claims or bankruptcy court. The filing of a court action to enable the recording of a notice of pending action, for order of attachment, receivership, injunction, or other provisional remedies, shall not constitute a waiver of the mediation and arbitration provisions.
As shown above, Para 17B(2)iv appears to exclude matters within the jurisdiction of small claims from mediation and arbitration. So, if it costs less than $7500 to "make you whole" an easier, though perhaps not optimal, option is small claims.
This aside, it never hurts to get a true legal opinion because getting a complete picture of your circumstance requires a much longer discussion than can be effectively supported here. This may be a simple or complex issue, as such; it never hurts to get a real legal opinion after a complete picture of your circumstance comes into focus.