Please ask this question directly to the Limesurvey GmbH via the "Contact Us" link. In the forum, most of us do not have this kind of information. But, if I recall right, you just need to buy another monthly package and you get the respective amount of responses.
Help us to help you!
Provide your LS version and where it is installed (own server, uni/employer, SaaS hosting, etc.).
Always provide a LSS file (not LSQ or LSG).
Note: I answer at this forum in my spare time, I'm not a LimeSurvey GmbH employee.
