The standard search API works on an incomplete index of up to 6-9 days of data. Brand new accounts, low quality Tweets that have been marked as spam by users, or other signals, may mean that certain Tweets are not available via the standard endpoint.
Only a very small proportion of Tweets carry geodata, as applied by users.
When you say “I need all of them” - all of what - all of the Tweets with a hashtag over the course of a 7 day period? The standard search endpoint will be unlikely to return all of the Tweets, but it might return enough for your purposes.