Problems with Solr data ingestion are generally out of scope for SearchStax Managed Search service support, except to mention that legacy data often includes illegal codes that you must remove, and most issues are ultimately traced to field misconfigurations in the schema file.
SearchStax has Solr Architects who provide Solr Advisory Services to premium clients on a contract basis. All others are advised to consult the Solr user community.
Questions?
Do not hesitate to contact the SearchStax Support Desk.