Create and update subscribers in c#

Hi Team I'm following below steps to create/update subscribers in Novu Creating subscribers is working fine. I can see subscribers in novu dashboard but update is not working am i missing somethig ? private async Task UpdateStudentData(StudentAggregatedDetails updatedStudent) { var filter = Builders<subscribers>.Filter.Eq("subscriberId", updatedStudent.UserReferenceId); if (filter != null) { var update = Builders<subscribers>.Update .Set(s => s.firstName, updatedStudent.FirstName) .Set(s => s.lastName, updatedStudent.LastName) .Set(s => s.email, updatedStudent.Email) .Set(s => s._organizationId, organizationId) .Set(s => s._environmentId, environmentId) .Set(s => s.data.NextEncounterDateInStudentTimeZone, updatedStudent.NextEncounterDateInStudentTimeZone) .Set(s => s.data.StartLevel, updatedStudent.StartLevel); await _mongoCollection.UpdateOneAsync(filter, update); } } public subscribers MapToSubscribers(StudentAggregatedDetails studentDetails) { var NewUser = new subscribers { // Map properties from StudentAggregatedDetails to subscribers subscriberId = studentDetails.UserReferenceId, firstName = studentDetails.FirstName, lastName = studentDetails.LastName, email = studentDetails.Email, createdAt = DateTime.Now.ToUniversalTime(), updatedAt = DateTime.Now.ToUniversalTime(), _environmentId = environmentId, _organizationId = organizationId, deleted = false, data = new Data { StartLevel = studentDetails.StartLevel, EndLevel = studentDetails.EndLevel, } };