this has nothing to do with kibana, its about logstash and correctly indexing your data.
fir example in your grok filter you set date variable ... but then in your date->match you are trying to use timestamp
https://www.elastic.co/guide/en/logstash/current/plugins-filters-date.html
i suggest that you always check your data in the discover tab in kibana first, check that fields have correct types and that you are seeing the right values.
as mentioned above grok debuger can also be of great help.