As you must be knowing there is no provision in law to challenge the decision made by lok adalat, so it can't be challenged by way of appeal, review, revision. nor u can file an application before the same lok adalat to reconsider its decision. the only option open is to file a suit for declaration in the civil court, but in that case you have to allege all thing including unauthorised withdrawal of case by the attorney but before filing that make sure to look into certain things
1. whether your client was present when the suit was withdrawn
2. on whose statement suit aws withdrawn
3. if it was your client who stated to have the withdrawal whether there are his signature on the statement made for withdrawal and whether he was identified by any person present there.
4. time expired since the date of withdrawal or when your client came to know about the alleged illegal withdrawal.
5. court often do consider the prejudice that has happen to your client by such withdrawal and the extent of the prejudice.
what is written above are the recoureses open to you,
you can also intiate legal proceeding against the culprit lawyer in the consumer court plus you can also intimate bar association so as to initiate inquiry against the lawyer which even could suspend his practising license.