Can I file for summary Judgement on the grounds of the defendants refusal to partisipate;If not what can I do?
No, but you could file a motion to compel -- then if they continue to ignore your discovery requests, they could be held in contempt or sanctioned by the court.
California Code of Civil Procedure, Section 2023(b):
"(b) To the extent authorized by the section governing any
particular discovery method or any other provision of this article,
the court, after notice to any affected party, person, or attorney,
and after opportunity for hearing, may impose the following sanctions
against anyone engaging in conduct that is a misuse of the discovery
process.
(1) The court may impose a monetary sanction ordering that one
engaging in the misuse of the discovery process, or any attorney
advising that conduct, or both pay the reasonable expenses, including
attorney's fees, incurred by anyone as a result of that conduct.
The court may also impose this sanction on one unsuccessfully
asserting that another has engaged in the misuse of the discovery
process, or on any attorney who advised that assertion, or on both.
If a monetary sanction is authorized by any provision of this
article, the court shall impose that sanction unless it finds that
the one subject to the sanction acted with substantial justification
or that other circumstances make the imposition of the sanction
unjust.
(2) The court may impose an issue sanction ordering that
designated facts shall be taken as established in the action in
accordance with the claim of the party adversely affected by the
misuse of the discovery process. The court may also impose an issue
sanction by an order prohibiting any party engaging in the misuse of
the discovery process from supporting or opposing designated claims
or defenses.
(3) The court may impose an evidence sanction by an order
prohibiting any party engaging in the misuse of the discovery process
from introducing designated matters in evidence.
(4) The court may impose a terminating sanction by one of the
following orders:
(A) An order striking out the pleadings or parts of the pleadings
of any party engaging in the misuse of the discovery process.
(B) An order staying further proceedings by that party until an
order for discovery is obeyed.
(C) An order dismissing the action, or any part of the action, of
that party.
(D) An order rendering a judgment by default against that party.
(5) The court may impose a contempt sanction by an order treating
the misuse of the discovery process as a contempt of court.
(c) A request for a sanction shall, in the notice of motion,
identify every person, party, and attorney against whom the sanction
is sought, and specify the type of sanction sought. The notice of
motion shall be supported by a memorandum of points and authorities,
and accompanied by a declaration setting forth facts supporting the
amount of any monetary sanction sought."