Search API - longer retention time of Tweets for research



I am doing my thesis on improving accuracy of market forecasting with sentiment analysis on Twitter data and I am stuck on 7 day retention policy of Tweets. It is pretty crucial for me to get at least one month Twitter data containing some tag but what I’ve read it is only available for enterprise. Is there any way I can get the data? I can pay for it, no problem, but I think setting up a request to the sales team is a bit of an overshoot.