As of April 12th, you must go to Progress SupportLink to create new support cases or to access existing cases. Please, bookmark the SupportLink URL and use the new portal to contact the support team.
The latest pricing/limits/rules can be found here: http://www.kinvey.com/pricing and http://www.kinvey.com/pricing-starter
Currently, for the development plan, the important limit to worry about is the number of active users - the limit is 1k/month. Also, the current limit on data storage is 30 GB.
As of now, there is no such limit on the number of requests. But, Kinvey does monitor for request/load spikes to safeguard our multi-tenant setup against disruption.
I hope this helps.
Is there a limit of number of request for the Development version?