First you need to remove the resource corresponding to the application itself:
Remove-AzureRmResource -ResourceId /subscriptions/$subscriptionId/resourcegroups/$resourceGroupName/providers/Microsoft.ServiceFabric/clusters/$clusterName/applications/$applicationName -ApiVersion "2017-07-01-preview" -Force -Verbose
And then the resource corresponding to the service:
Remove-AzureRmResource -ResourceId /subscriptions/$subscriptionId/resourcegroups/$resourceGroupName/providers/Microsoft.ServiceFabric/clusters/$clusterName/applicationTypes/$serviceTypeName/versions/$serviceTypeVersion -ApiVersion "2017-07-01-preview" -Force -Verbose